hodorskib's Small Scale RO Build

[troynh]

Thanks Bret for a well thought out tutorial and parts list c/o this small scale RO build. Now it's hurry up and wait for next year.
I still have to build my feed tank area which will be in the garage up those stairs in the picture. No rush, I have all year...;)

Find the build info here: https://sites.google.com/site/mattatuckmadnessmaplesyrup/home/homemade-reverse-osmosis-system

-Tim

[wobbletop]

Nice tidy setup!

[hodorskib]

You are welcome and very nice setup - hopefully next year will be a good one

[jrako724]

Bret,
Love the unit you designed. Would you have any ideas on how to make it a bit larger? We get about double that amount per day and i'd like to build a unit with as many of the same parts you did. Can we use the same pump and split the flow between 2 sets of filters? How would you preheat the sap and whats an ideal temp? I'm new to RO but would love to try this and have to burn less wood. Thanks
Jeremy

[themidnightsapper]

We are looking at building our first RO for the upcoming season. What would be your thoughts about adding a couple more membranes in order to get to a 10 - 12 percent concentrate? Biggest questions is if the pump will maintain the pressure across additional membranes. Thanks for posting this system and any input you have would be appreciated!

[hodorskib]

If you are looking for a larger RO you may want to search for the one Diesel Pro put together that would be better. The setup I use is really for around 75 taps or 120 gallons or less per day. You could run two setups but then you are at the cost of the larger systems others have built.

[Clinkis]

Built this same RO and used it for 2 seasons. Works great but has limited capacity. If your are collecting under 100 gallons a day and want to remove 50-60% of your water this system will work great. Can go to higher concentration but your flow rate drops off.

Adding additional membranes will not increase the capacity of this system. There is not enough flow from the pump. If you want more capacity you need to use commercial RO components which are readily available and will not break the bank if you want to build a simple RO.

[hodorskib]

From my research and experience I have found that once you go above 8-8.5% residential membranes begin to foul quickly. I run mine with 4 membranes and I am looking at possible adding one or two more this year not to increase concentrate but to increase the flow. Not sure if it will work but I think I am going to give it a shot the theory of going through two more membranes with less back pressure should give me the same concentrate level but at a faster rate of process.

[themidnightsapper]

Thanks for the info. This will be our first RO, we expect about 100 taps this coming season and was hoping to get to a 10-12% sugar content using RO. Last year was our first try an making more that a pint or two of syrup...we had 65 taps on a very good gravity system....no RO and a homemade block arch evaporator. Needless to say we were overwhelmed and hope to be much better prepared this season.

[wlatrout]

If you uped the membranes to 200 GPD instead of the 150 GPD would you need a bigger pump and would how much would your GPD rise? Or would it be better to just add 2 more membranes?

[hodorskib]

The pump should be able to handle the 200gpd membranes but it may be more cost effective to go with an extra 150gpd membrane. This year I am trying to run 6 in series with a 10ml flow restrictor. Hoping to increase rate of process while keeping the concentrate at around 7%.

[SDdave]

Not to hijack this thread but what type of chemicals have people used to clean the membranes?

I've used the h2o2 routine, but my sister who is a chemical something or other said i was just using glorified water. How long do the membranes last?

I want to give the system a really good cleaning this year.

SDdave

[hodorskib]

I have always used a solution of hydrogen peroxide and water: Cleaning the membranes
https://sites.google.com/site/mattatuckmadnessmaplesyrup/home/homemade-reverse-osmosis-system

This will be my third year with 150gpd membranes.

[troynh]

Bret,

My system is finally up and running! This thing is awesome! However, I have a question... In testing my water, I'm reading a 0.2%. Brand new everything as far as membranes and filter. What can I change to get that to read 0%?

I can't believe how sensitive the valve is c/o output pressure and sugar content! Amazing.

Thanks again,

-Tim

(PS - My initial sap content was 2.3%. It's now a steady 7.3% straight from the barrel.)


https://www.youtube.com/watch?v=uIX5djzmZvQ&feature=youtu.be

[Bricklayer]

I find with my Hanna digital refractometer, If I leave the sap or syrup whatever I'm testing in the stainless test cup, eye or whatever you want to call it for 20 seconds to let the temp level off it will get a better reading. The temp compensation reading is the numbers on the bottom. And after you test your concentrate put a couple drops of permeate in there and slosh it around to get the eye clean then wipe it. Might have a little residue in there. They are pretty finicky. and 0.2% sugar is basically nothing. I bet if you clean it then test it will be 0.0%

[troynh]

That's the ticket! I'm back to 0%. I was rushing it....

Thank you,

-Tim

[hodorskib]

troynh
glad to hear everything worked out - I did add two additional membranes this year (6 total) and I am getting a process rate of 10 gallons per hour to a 7.5% concentrate starting with 1.5% sap. I installed 3/16" tubing and I have been flooded with sap so this really helps.

[troynh]

Excellent! So that flow resistor is working! This is next years project. lol...

[hodorskib]

The flow restrictor (150ml) did not work as well as I was hoping I was only getting it to 6% with 6 membranes so I went back to the needle valve. However, another guy shared a pressure relief valve that is more precise and once it is set you are all set. Will be trying it later this year. Here is a link for it:
http://www.sprayerdepot.com/Shop-by-Category/Relief-Valves/AA11014300

[troynh]

Thanks for the update! Yeah, the needle valve needs to be babysat every hour or so. I'm finding it likes to wander slightly. Overall though, this setup is the ticket for small scale! :-) Very happy!

-Tim

[wobbletop]

Better to start with a needle valve, or a flow restrictor? I'm planning on using a single 100gpd membrane to start since I only have 10 taps right now. How to size the restrictor?

I found this site... http://www.purewaterproducts.com/articles/flow-restrictors

But I'm sure that's for normal tap water temperatures, and not near freezing temperature sap. That will reduce the flow rate, and then how to calculate the proper restrictor? I'm liking the idea of the restrictor vs babysitting a needle valve.

Also, can you adjust the needle valve by monitoring pressures in the system somewhere, or are you always measuring flow rates instead?

[mspina14]

Brett:

Thanks for an excellent overview of a small scale RO system.

I'm pondering something like this for next year.

Can you provide the type of membrane and membrane housing you are using and where they can be found?

thanks

Mark

[troynh]

https://sites.google.com/site/mattatuckmadnessmaplesyrup/parts-list-for-ro-system

[mspina14]

https://sites.google.com/site/mattatuckmadnessmaplesyrup/parts-list-for-ro-system

Thanks Tim.

Mark

[MapleSaint]

This was very helpful. Thanks guys. Wish I found this thread before I started one of my own.

[hodorskib]

Wobbletop:
With 10 taps a single membrane will do fine. You will just keep recirculating it back into your feed tank and will eventually get up to a 6+ concentrate level. You will try for a 1 part permeate to 3 or 4 parts concentrate. This will keep the membrane from fouling and work much better. You can use a needle valve it will be fine since you will not be creating much back pressure or a flow restrictor. The smallest I found was a 150ml size you might want to go a little larger for recirculating though.

[wlatrout]

Hodorskib, I built an RO to your specks , I was getting 10 gph . My sap was mostly 1 1/2 % with some from sugar maples at 2 1/2%. On the 1 1/2 % I was getting 6% concentrate , the 2 1/2 %was higher. I used a 150 gph flow restrictor. Would I get a higher % concentrate with a pressure flow valve. Also I am a little confused about the soap to clean the membranes. Or do you just use the Peroxide ?
I greatly appreciate all the information you provided. It was an easy build and saved a ton of time and wood.

[hodorskib]

Glad it worked out for you. The flow restrictor I tried this year gave me the same results around 6% so I went back to the needle valve. However, another guy who built a system a few years ago sent me a link for a pressure bypass valve and after using it for the last week or so of my season it was worth the extra money. Here is a link for it:
http://www.sprayerdepot.com/Shop-by-Category/Relief-Valves/AA11014300
This allows for much better control and the ability to go to 8% and unlike a needle valve once you set it you don't need to keep adjusting.
As for cleaning I will be updating the website as soon as I get a chance but this year I plugged my membranes really bad and needed to think about a better way of keeping them clean. Here is what I came up with after talking to others with similar systems: I will be doing this once a week
1. Change your water filter
2. Open the membrane housings and dump out any liquid in the top - there is usually some slime and gunk especially toward the end of the season
3. Flush with permeate for 20-30 minutes
4. Fill a 5 gallon bucket with warm water and put 1 quart of hydrogen peroxide in
5. Run that through the system recirculating it back into the bucket (just take your concentrate and permeate lines and put in the bucket) and let run for 1 hour
6. Replace the water filter and flush with permeate for 20-30 minutes (leave the water filter in place you will use it for the next run)

This is also what I did at the end of my season then wrapped the membranes in plastic wrap put in a zip lock bag and they are in my beer fridge for next year.

Let me know if you have any other questions: huu133@gmail.com

[eustis22]

hi..can you explain the relationship between the pressure valve and the % of the concentrate? How does one affect the other?

[hodorskib]

You need to install something to create back pressure on the concentrate line. It can be a needle valve, flow restrictor or by-pass valve. This is what forces the water through the membranes. The more back pressure the more water is removed which gives you a higher concentrate. However, the higher the concentrate the less gallons per hour you can process so you have to play around a little to see what works for you. For me the balance this year was between 7 and 7.5% and with 6 membranes I was able to process 10 gallons per hour when the sap was around 50 degrees and 6-7 when below 40 degrees. Hope this makes sense.

[jplewes]

Just wanted to chime in and say thanks for these great plans.. I built this system for my tiny hobby setup here in Quebec, Canada. I'm not as deep into the technical yet to determine % sugar yields or flow performance, but i do know it saves me a bunch of hardwood and time!

Here is a photo of the rig on the inside door of my shed.. 3 x 45 gallon drums inside to hold the sap, permeate, and concentrate. There is a small heater to keep the room just the right temp and a bunch of float switches to turn the pump off by relay if the levels are about to run out or overflow.

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-Jeff

[hodorskib]

I have had many people send me pics of their setups from the plan but I have to say yours is at the top of the list! That is a nice setup.

[wlatrout]

Wanted to post a picture of my sugar room earlier but couldn't get it to work.So here it is.16335

[wobbletop]

^^^ Very nice!

[SDdave]

wlatrout: very nice set up. Always looking for a nice and neat way for the RO system.

To everyone who has more than 3 membranes in series: What's the advantage? What size of membranes are you using? Operating PSI? GPH of raw sap? I ask because I use the 150 gpd membranes at 125 to 130 PSI and get 9-10 gph of raw sap to around 7%. I do have extra housings and membranes to use, just have never considered adding them; except for another RO setup. More curious than anything.

SDdave

[hodorskib]

Very nice setup - I have 6 150gpd membranes in series and was taking 1.3% sap to 7-7.5% in a single pass at a rate of about 10 gallons per hour and running at around 145psi. Just be careful on what your membranes are rated for - some are 150 and others are 125.

[Mark B]

New to the boards here, but after visiting a couple local sugar houses, I thought, why cant I do this small scale. This discussion is exactly what I was looking for. My Uncle, who has a quaint little sugar shack here in Maine, passed away this year in January and while Id never sugared before, I figured I would try it out. I came to the dance a week or two late, but had fun working his lines. However his stove is way small and I spent too much time burning wood and gas to get my 7.5 gallons so far. The wife now considers me obsessed. Found a cheap stove ($40) that I can fit a roughly 2 x 3 pan to, with plans to modify and use next year. (Looking for a cheap 20-24" x 36" pan for it, and for the right price I will travel or pay shipping)

Then I started thinking RO and ran across hodorskib's RO build on Pinterest which eventually led me here. Awesome discussion and very easily understood. Wife has given in on my idea to build a small scale RO before next season as long as I come up with a way to pay for it. I guess I'll part with a couple of deep sea reels and a couple of collectibles I'm hoarding. Anyway, gonna clear out the garage this year and convert it to my shack for next season. Thanks again, Mark

[jplewes]

I have had many people send me pics of their setups from the plan but I have to say yours is at the top of the list! That is a nice setup.

Thanks! It doesn't hurt that the other side of the shed is a sauna :) Gotta do something while the evaporator is running right?

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[Mark B]

Has anyone looked into the Membrane Solutions ro membranes on EBAY? Investigated online and they are supposed to ptfe-tfc membranes. I know the parts list shows Axeon membranes. I'm slowly aquiring parts to build the ro this fall but don't want to drop money on a product that isn't quality or applicable. It appears they can operate in the 125-150 psi range. And if applicable could you plumb in a couple of the 10"x3" 300 or 400 gpd to increase flow over the 150's? New to this technology, so I'm asking here, cause the only dumb question is the one you don't ask and then end up paying for later. Thxs, Mark

[hodorskib]

Just checked them out and they should work - just don't exceed the maximum psi.

[Mark B]

Thank you for investgating and answering.

[hodorskib]

Mark B:
I contacted the company and the membranes can go up to 300psi without damaged. They also recommend for maximum performance to keep it at 150psi or less. Interesting part is on the ebay site they also offer 400 gallon per day membranes with housings for around 75 dollars. In theory you could use two of these and should be in good shape and save a little money.

[Mark B]

I found them in 300s and 400s. One of the auctions offers the housing with them. I think the 300 with housing was $63 and the 400 was $72. I was actually thinking of buying the 300s. I could then set all 4 in series like your build or parallel plumb two sets of 2 (in series). That then led me to consider plumbing the whole thing in 3/8 for better flow. Would the 8800 pump still be able to maintain​ pressure on this system plumbed in 3/8?

[eustis22]

How do you keep your outside ROs warm?

[Mark B]

I don't know about the rest here, but I plan on mounting mine to a wood Dollie and making it portable. I will keep it in my mudroom entry which hovers in the low to mid 40s. Im making it portable so it can do time between my home and my bro in law who also sugars.

[hodorskib]

The aquatech 8800 is rated for 1200gpd I was also looking at plumbing larger membranes and housings with 3/8" tubing to increase the flow. Just not sure when it will reach its capacity. A lot of folks have mounted theirs to hand trucks to make them portable with the pump mounted to the bottom plate this way you just move it inside to keep from freezing. Others have built a simple box out of insulation boards duct taped together then put a small lightbulb or other heat source inside. Possibilities are endless you just want to make sure it doesn't freeze.

[Mark B]

Hoping I can push the 2x4 into the 12-15 gph for evap rate and I can get the ro into the 14-18 gph rate at about 7-8%. Theoretically, I could contacentrate into my warmer and stay just about even with the boil. It would be much nicer next year to have 4-6 hour days as opposed to 14s.

[eustis22]

What needs to be kept warm, the water filter and the membranes? Would it be possible to have those with quick connects so I just need to hook them up during RO time?

[hodorskib]

Everything is put together with quick connects and I wouldn't let anything freeze but the membranes in particular.

[Ken18621]

I finally got all the parts together to make this ro. I was doing a test run with straight well water and noticed water coming out of both permeate and concentrate lines. This doesn't make sense to me, it's just straight well water, why is it coming out of both lines?

[Super Sapper]

You should have water out of both lines if you have enough pressure on the concentrate side. There will be concentrated minerals in the concentrate side and should be pure water on the permeate side.

[Andrew Franklin]

Bret, I built a pretty much a replica of your system and used it last year and loved it - thanks for the easy to understand instructions! I did commit a sin...I flushed with a couple of gallons of permeate thinking I would boil the next weekend, and the temps shot up and what I collected that week spoiled. I had the membranes wrapped and in the fridge, but somehow forgot to give them the deep clean. I pulled them out last night and noticed two things...a faint odor, and a little ice since they were on the bottom drawer of the fridge. Don't think they totally froze, but can't guarantee it. So, I doubled up on your normal end of season cleaning with hydrogen peroxide, and they look good, but just in case I ordered a new set of 4 150 gpd membranes ($31 each on amazon).

My question...given my poor treatment of the membranes should I even try them? My thought was they hopefully are clean after a 2 hour hydrogen peroxide bath and 40 gallons of water rinse and won't ruin my sap, and I can test to see what performance I'm getting and switch out if it is off, but my sap and time are both short and don't want to waste much of either...if they are shot after possibly freezing or with the sap in them all year I'll just pitch them and consider it a lesson learned.

Thanks in advance for your input!

[Andrew Franklin]

One thing I forgot to add...I also make beer and have a wort chiller that is basically a big coil of copper pipe that you run cold water through to cool it quickly. I'm going to do that in reverse...have a wood fire under a turkey fryer pot and run my sap through the copper coils prior to the ro to warm it (I hope) to around 100 degrees. Sap in the pot of course, so I'm warming raw sap which can go into my pre-ro tank to recycle or straight into the evaporator...whichever is ahead of the other. Seems worth a little wood given the yield through the ro with warm sap vs cold.

[hodorskib]

I wouldn't toss them yet - warm up a five gallon bucket of water and 2 bottles of peroxide to about 90 degrees and let it recirculate for an hour or so. Then flush with water for about 30 minutes. Take them out and give it the smell test. As for warming the sap make sure it doesn't get too warm you will cause bacteria to bloom throughout the system. I did purchase some RO soap this year and checked the manufacturers specs on my membranes for ph levels and will be giving that a try. Will post everything after I give it a whirl.

[Andrew Franklin]

Thanks for the tips...I'll give them a try, and it will be easy to adjust the temp on the sap...I'll just mix it with cold and play with the temps and keep it as low as I can with a high flow rate.

[Mark B]

Brett, I hope nobody is offended, I duplicated this post. This was based on your design with input from several other folks. Here is my newly built Reverse Osmosis for sapping this year. Hoping to remove 2/3 to 3/4 of the water from my sap with this RO. Pump is an Aquatech 8852 with 3/8 outlets and is a 1200 gpd pump paired with 3 x 400 gpd ro membranes. The membranes are plumbed in parallel with a 300ml recirculation line. Hoping to process about 60 gallons of sap per hour at about 7-8%, (but hopeful for as much as 80).

I had this laid out once before, but I came across a dry sink cabinet for free. I've reorganized and plumbed it to fit the cabinet. Ill be building a cart base on the cabinet this week and hinging this to the open back.

I have about $500 in this build.

https://m.facebook.com/story.php?story_fbid=1859761970710298&id=100000295385959

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[Clinkis]

Hi Mark, nice build. You'll sure like boiling concentrate over raw sap.

I'm just a little confused about where you are getting your 60-80 GPH processing rate. When you look at the 8852 pump specs the flow rate is around 40 gph at 0 psi but drops to around 11 gph when you push it up to 130 psi which is what you will need to do to get it up to 8%. Even then you may need to do multiple passes to get it that high. Here are the pump specs. Chart is in litres per minute.
https://www.freshwatersystems.com/specifications/8800_RO_Booster_Pump_24Vac.pdf

If I'm missing something my apologies. I'd just hate for you for you to be overwhelmed with sap if you have miscalculated.

All the best this season

[Mark B]

May have stated that a little confusing and I may be misunderstanding something. I'm actually hoping for 15-20 gph of concentrate at 7-8%. Ill be happy if I can get in excess of 12 gph. I believe Brett had pushed his into the 8-10 range and I am hoping with added capacity to better that by a few gph. I was also told that the 8800s were 50gph. So anyway, while I have a rudimentary understanding of hydraulics, I don't know enough to make a really good guestimate, and was hoping the added capacity would allow me to max the pump and push it into my hoped for range. It will be my 1st year and definitely a learning year.



Thanks for the link to the spec sheet.

[Clinkis]

Yes the 8852 will do a little over 40 gph at 0 psi but unfortunately it drops off signicantly when you get it up over 100 psi. This is normal with most pumps except positive displacement. And in order for your membranes to work you need this higher pressure. When I was running Brett’s setup with an 8852 I was able to process 8-10 gph of sap producing 5-6 gph of concentrate. Your setup may do better but you are still limited by the maximum flow of the pump.

[Mark B]

I may have misunderstood his original postings, thinking that when he was talking about 10 gallons per hour that he was talking about concentrate, when he was probably talking about how much raw sap he was able to process.

No matter how long it takes I will still be happy to cut my raw sap by two-thirds of its water.

[Clinkis]

One thing to consider as a future upgrade is to replace the pump with higher capacity pump like a small Procon. This would help you achieve a lot closer to your goal and take better advantage of your membranes capacity.

[Mark B]

Definite upgrade. Already researching and pricing.

[Clinkis]

So just keep in mind that membranes are rated based on permeate flow and that a certain processing flow rate is recommended to achieve this and minimize fouling. So for example your membranes are rated 400 gpd and usually most membranes require a minimum 5 to 1 feed rate to permeate flow rate (check the specs for your membranes) thus you should be feeding each membrane with 2000 gpd or 80 gph. Since your membranes are plumbed in parallel you will need 3 times that around 240 gph. This is usually why it is recommended for these types of RO’s to have membranes in series to obtain higher flow rates across the membranes without having to use a larger pump. I’d say your best plan would be to plumb your membranes in series and get a 100 gph Procon pump or something equivalent.

[Mark B]

I continue to be thankful for the generous outpouring of advise here. Again I'm just learning and this will be an interesting season. We will see if ambition, time, effort, and results all merge. Thxs again for the help.

[Blacksheep7]

Could some tell me if this tubing would work? It is listed at 140 max PSI. Menards is having a sale on anything you can fit in their recyclable bag for 15% off.

https://www.menards.com/main/plumbing/rough-plumbing/pipe-tubing-hoses-fittings-accessories/hoses-tubing/polyethylene-tubing/pe-tube-3-8-od-x-1-4-id-1-16-wall-white-25ft/p-1470660864282.htm

Putting my shopping list together right now to get everything bought or ordered this week.

Thank you,
Jason

[hodorskib]

You should be OK - I have used similar without issue

[Blacksheep7]

Thank you. I have either bought everything or have it on order. Do you or anyone use a low pressure shutoff or the pump? I am a bit afraid to leave it run.

Here is one I found.

https://www.freshwatersystems.com/p-4437-shurflo-low-pressure-shut-off-switch-14-push-fitting-wiring.aspx

Thank you,
Jason

[Clinkis]

It probably wouldn’t hurt but dont really need one. These pumps can run dry without damage. I used to put a plug in timer on mine so it would shut off when I figured it should be finished. But that might be easier and I guess it not that expensive.

[Blacksheep7]

Thanks to everyone for the great information here. I finally have everything put together(with many trips to Menards) and ready to run. I went with 3 - 400 gpd membranes and 1/4" line. I figure I can upgrade the line in the future. We are on well water and have a water softener. Can I use this water for the initial rinse of the RO membranes and then follow the water/peroxide mix that has been described in other posts? I would like to run this over the next couple of weeks to see if I have any troubles.

Thank you,
Jason
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[Mark B]

Biggest problem with the low pressure shut off is that you have to override them to start back up again so you will either have to use the override button on the low pressure shut off or you will have to make yourself an override switch and wire it in place.

I'll pretty much leave the initial rinse question to others but if you're talking about rinsing after your initial run you should be able to use your permeate for that.

[Blacksheep7]

Thanks Mark. I will see how the switch works out. I can always disconnect it.

As for the rinse, I am curious about before the first run. I have read you need to do an initial rinse to clean the membranes. I do plan to keep permeate once the first run is complete.

Thanks again,
Jason


Sent from my iPhone using Tapatalk

[SDdave]

First of all you will love this contraption when you are using it!

Before processing sap make sure you do the rinse. I used a couple 5 gal buckets. Fill both with water. Pump through these with the valve wide open. When working on the 2nd bucket, refill the first. Then run the system with valve as you would run sap. Pressure around 125ish. Run another 10 gallons like this. Refill buckets again and run wide open.

If you dare sample some of the first run of water. Then compare to the last run. Should taste like water when you are done.

SDdave

[Blacksheep7]

Thanks SDdave. I hope to run the initial cleaning rinse on Sunday afternoon.

[jdircksen]

I have a small operation currently, and next year might have 25 taps total. Is there a rule of thumb for # of RO membranes and size vs the number of taps? Meaning...should I use 2x 100gpd, or 3x 100gpd, or 2x 150gpd?

[eustis22]

I recently purchased a couple of 30 gallon HDPE barrels that were sold as "food grade". It turns out they were used to store zinc orthophosphate which is a water additive so I cannot use them for sap (concentrate or other). BUT..can I use them for permeate storage? If so, what is the effect of rinsing my membranes with permeate stored in these?

[jdircksen]

Another question...why is my pressure so low? I am running an Aquatec 8852, 5 micron prefilter, and 3x 150gpd membranes. All the components are brand new. City water has been in my 62*F basement for 4 days to let the chlorine evaporate. I just turned it on today to flush the membranes and these are the pressure readings after 2 hours of running.

With the valve fully closed, the pressure goes to 65psi and there is moderate flow from the permeate line.
With the valve adjusted so that I get a 50/50 mix of concentrate/permeate, the pressure is at 40psi.
With the value fully open, the pressure is at 20psi and there is still a small, steady flow from the permeate line.

[eustis22]

So I'm getting ready to assemble and use this RO this weekend and I need to know if I can use ordinary tape water for the initial rinse of my membranes?

[jdircksen]

You are not supposed to use tapwater because it has chlorine and that will damage the membranes. But if you let tapwater sit out for a few days the chlorine will evaporate.

[Mark B]

Or you can cheat and buy the water treatment we use in our home aquariums to neutralize the chlorine so it does not harm the fish. The local pet stores will have it... one bottle will treat hundreds of gallons.

[SDdave]

Another question...why is my pressure so low? I am running an Aquatec 8852, 5 micron prefilter, and 3x 150gpd membranes. All the components are brand new. City water has been in my 62*F basement for 4 days to let the chlorine evaporate. I just turned it on today to flush the membranes and these are the pressure readings after 2 hours of running.

With the valve fully closed, the pressure goes to 65psi and there is moderate flow from the permeate line.
With the valve adjusted so that I get a 50/50 mix of concentrate/permeate, the pressure is at 40psi.
With the value fully open, the pressure is at 20psi and there is still a small, steady flow from the permeate line.

If no one has answered yet...

On my system I had to adjust the pump, and use back pressure. On the pump there is a set screw that needs to be adjusted with an Allen wrench. I would close the valve and have the system run, adjust the screw (1/4 turn at a time) the pressure should go up. Then open the valve slightly to obtain the flow you desire. I try to run around 125 psi when processing sap.

SDdave

[hodorskib]

You will not build pressure running just water. You will see the rise in pressure when you start running sap - wait to adjust until then. Good luck

[sweetvt]

A few questions about these small scale ro's:

What is the advantage/disadvantage to plumbing these hobby ro's in series vs. parallel It looks like Hordoskib's uses series and something like the RO Bucket has them in parallel design. Curious as to what others have found? The RO bucket has larger membranes (GPD) and looks like a larger pump (not sure what pressure their pump will achieve) . Their RB -15 model claims to process something like 20 -25 GPH of water or 10 gals of concentrate per hour.... I regularly collect 75- 140 gals when the sap runs and can evaporate 18- 20 GPH. I am trying to decide if one of these hobby RO's will process sap in a timely enough manner so that I don't end up having concentrated sap sitting around for a day plus waiting to boil. As with most, I have a day job and collect in the afternoon after work and usually boil at night.

If what I read about these rates for these small ones is accurate, I would need to plan to have the Ro on some type of timer to process the next day and have it concentrated for the next days boil that evening. Also if these type of RO's were concentrating to say only 5% could I expect an increase in the gph concentrate and how much 5% could I expect per hour?

Thanks

[ecolbeck]

I think a good general rule is that for a given system flow and concentration are inversely proportional to each other. You can have either have high flow through the system or high concentration but not both. A system plumbed in series will produce a more concentrated sap but at a slower rate. A system plumbed in parallel will produce more output but at a lower concentration. Cold sap seems to slow it down too.

I’m using the RB15 kit feeding straight into a cdl 18x48 drop flue running at 12-15ish gph. Yesterday I boiled 60 ish gallons of sap in about 4 ish hours and pulled out about 20 ish gallons of permeate. This was all on the fly I did not have time toconcentrate anything ahead of time. I didn’t run the RO at full capacity because I was feeding the pan with the pump

Hopefully all of this blabbering answers your question an gives you an idea of what the kits can do. I’m really happy with mine so far.

[Clinkis]

Another reason that many people plumb these types of RO’s in series is to maintain a higher flow rate acrosss each membrane and thus you get a lot less fouling. When I ran this style of RO I tried it both ways and found series worked the best. I was using an 8852 Aquatec pump.

[hodorskib]

I have tried it both ways and found the series works best for me. I run mine while I am sleeping or at work and found that a single pass to a holding tank gives me a better quality syrup in the end. Everytime it passes through the pump it heats up the sap - so by just going through once it limits the heating. Also, I have found that it takes roughly the same amount either in series or parallel to process. One drawback to running in series is you need to clean often. With this said I did build a new system this year with 3 - 400gpd membranes in series and although fixing some leaking issues I was taking 1.2% to 8% in a single pass at a rate of 12 gallons per hour. I am also using an RO soap instead of just peroxide to keep the membranes clean. I will be posting all my results at the end of the season to my website.

[eustis22]

so I built this, and I am finishing up the connections, and my tubing is just sliding out of my needle valve. Is that supposed to happen? I have the tubing thru the olive

[edit]

nm...apparrently you have to really torque down the nut

[sweetvt]

Hodorskib, , is that 12 gph of concentrate? If so that is a decent increase by going with the larger membranes 400 vs the 150gpd correct? The aqua tech pump handles these with no issues? Are your sap temps in the 30’s something degree range ? So if I understand you correctly after you collect you ro and then boil concentrate the next day? Any issues with concentrate going bad? In looking at your past yearly logs I see you are making a good deal of Amber or lighter grades still?

Last question, is there a source online for the soap you are using and as time permits can you describe the cleaning process with the soap ?

Thanks

[eustis22]

in addition to sweetvts questions, does the rinse permeate have to be a certain temperature?

[hodorskib]

The rate of process is 12 gallons total - since my sap has been running 1.2% or less I have been removing about 85% of the water (so around 2 gallons of concentrate to 10 gallons of permeate).

The soap I am using is from CDL - https://webstore.cdlusa.net/en/Catalog.aspx?Hi=022009001&ps= this is an organic product and was under 20 dollars so that is why I selected it.

The flushing and cleaning process I have been using this year:

After each time I run the RO I take 5 gallons of permeate in a bucket (1.5 - 2 gallons I put in a pot and bring to a boil then add it to the cold stuff - this gives me a temperature between 90-100 degrees *** don't go over 100 degrees) then run it through the system with the needle valve wide open and both the permeate and concentrate lines back in the bucket of warm water. I let this recirculate for at least an hour.

For cleaning - I have been doing after every two or three days of operation (this will increase as the season goes on with more bacteria building in the system) I take the same warm permeate but add the RO soap to it until it reaches a PH of 11. Then recirculate as above for 1-2 hours. It is amazing how this stuff works. For me I needed to about 1 level tablespoon of soap powder to achieve that level. So the 1kg container will be enough for me to do like 40 or 50 washings. Then I flush with permeate for at least an hour - this time letting it flow down the drain. If you don't have access to the soap right now I have heard back from some other folks who are using similar systems using 2 quarts of hydrogen peroxide instead and getting good results as well.

I have processed 400 gallons of sap this week and it seems to be working well. Last season as things went along the performance of my membranes deteriorated which is why I am trying the ro soap this year. I have also checked with the manufacturer specs on my membranes and 11ph is the max level.

I will be posting everything to my website at the end of the season to make sure it all works out - but there seems to be enough interest to put out what I am trying now.

The last question about letting the concentrate sit - yes I run my RO while I am sleeping or at work so yes it does sit sometimes for 12-16 hours. I wish I could boil right away but this is a hobby and not my job so I do what I can. It is stored either on the North side of my house in the shade or in my garage which is about 55 degrees. If we get warm weather I will freeze some concentrate in milk jugs and put them in the holding tank during the day. Over the past 6 years using the RO I would have to say 85% of syrup produced as been Amber with the rest being Dark and last year made some really dark stuff.

[Blacksheep7]

Hodorskib, I built mine with 3-400’s as well, but used 1/4” line. Is yours built with 3/8”? Do you think I will loose much flow by this? I thought I would start with this and upgrade the line if needed.

Thanks,
Jason


Sent from my iPhone using Tapatalk

[hodorskib]

Mine is all plumbed with 3/8" tubing and I have a reducer on the concentrate line that brings it down to 1/4". I did this so when I cleaning or flushing the system I have it at 3/8" but when operating it reducing to 1/4" makes it easier to control the flow with a smaller needle valve.

[Blacksheep7]

Thanks. I will run it this way and see how it does. Probably a couple weeks before I get to use it yet.


Sent from my iPhone using Tapatalk

[carls47807]

Three membranes with a 400gpd booster or smaller will not need more than 1/4" hose. If you start getting to 60 or 70 f the membranes might pass enough permeate to require a 3/8 inlet. I tested it with both and there was no noticeable difference in flow/inlet pressures at 40f.

[Ken18621]

A huge thank you to hodorskib for posting the info. I built the RO according to the plans and I was able to take sap from 70- 1 ratio to an 11-1. Running 1.25% sap at 115 psi took me to 7.5%. 17817

[eustis22]

note to self: overtorquing the compression fittings distorts the brass olives and causes leaks. I was only able to get to 10 PSI testing/washing the membranes before finding the warped olives in my pressure gauge and needle valve

clearly god does not WANT me to RO her sap.

[hodorskib]

Yeah I have been there with you over doing it with the fittings. I have found that it is easier to tighten a little more later than finding replacement fittings. Also, I have always used teflon tape on all my fittings and sometimes they need a lot of wraps. Came across this product from oatey the other day. It worked really well with fewer wraps. https://www.homedepot.com/p/1-2-in-x-260-in-PTFE-Thread-Seal-Tape-306212/203529858

Ken - you are welcome and glad to hear everything went well. I will be posting everything I have been experimenting with at the end of the season.

[blurr95]

The rate of process is 12 gallons total - since my sap has been running 1.2% or less I have been removing about 85% of the water (so around 2 gallons of concentrate to 10 gallons of permeate).

The soap I am using is from CDL - https://webstore.cdlusa.net/en/Catalog.aspx?Hi=022009001&ps= this is an organic product and was under 20 dollars so that is why I selected it.

The flushing and cleaning process I have been using this year:

After each time I run the RO I take 5 gallons of permeate in a bucket (1.5 - 2 gallons I put in a pot and bring to a boil then add it to the cold stuff - this gives me a temperature between 90-100 degrees *** don't go over 100 degrees) then run it through the system with the needle valve wide open and both the permeate and concentrate lines back in the bucket of warm water. I let this recirculate for at least an hour.

For cleaning - I have been doing after every two or three days of operation (this will increase as the season goes on with more bacteria building in the system) I take the same warm permeate but add the RO soap to it until it reaches a PH of 11. Then recirculate as above for 1-2 hours. It is amazing how this stuff works. For me I needed to about 1 level tablespoon of soap powder to achieve that level. So the 1kg container will be enough for me to do like 40 or 50 washings. Then I flush with permeate for at least an hour - this time letting it flow down the drain. If you don't have access to the soap right now I have heard back from some other folks who are using similar systems using 2 quarts of hydrogen peroxide instead and getting good results as well.

I have processed 400 gallons of sap this week and it seems to be working well. Last season as things went along the performance of my membranes deteriorated which is why I am trying the ro soap this year. I have also checked with the manufacturer specs on my membranes and 11ph is the max level.

I will be posting everything to my website at the end of the season to make sure it all works out - but there seems to be enough interest to put out what I am trying now.

The last question about letting the concentrate sit - yes I run my RO while I am sleeping or at work so yes it does sit sometimes for 12-16 hours. I wish I could boil right away but this is a hobby and not my job so I do what I can. It is stored either on the North side of my house in the shade or in my garage which is about 55 degrees. If we get warm weather I will freeze some concentrate in milk jugs and put them in the holding tank during the day. Over the past 6 years using the RO I would have to say 85% of syrup produced as been Amber with the rest being Dark and last year made some really dark stuff.

How do you test your ph levels in your soap.

Jason

[hodorskib]

I picked up a digital ph meter for under 20 bucks but you can also use test strips that are only a few bucks.

[eustis22]

does it take a while to get to 115 psi? Should I leave my needle valve closed all the way until the pressure gets up?

[hodorskib]

Are you running sap or just water to test?

[eustis22]

Just water. I boliled the tap water to get rid of the chlorine. Might go 5 gals distilled water after I fix my olives.

[hodorskib]

That is normal with just water. Once you put sap through it the pressure will build.

[eustis22]

once I've rinsed out my new membranes, then what? I can just let em sit for a few days til I get sap again?

[hodorskib]

Give them a quick rinse (5-10 min) every other day until your sap start flowing. Then give a good rinse - 30 minutes before you put sap through it.

[eustis22]

rinse with what? all I have is tap water

[metalhead62]

eustis22 you save the permeate from what u ran though it the time before

[eustis22]

yeah I just used distilled water to clean the membranes. I assumed the permeat was full of membrane stuff and pitched it. no worries...Ima grab some spring water up north this w/e

[wobbletop]

I've been seeing designs with the aquatec pump between the filter and the first membrane. I've always had my filter after the pump.

Is the pump able to draw enough through the 5u filter? I imagine this would gain some extra pressure across the membrane.

[jwith]

I've been seeing designs with the aquatec pump between the filter and the first membrane. I've always had my filter after the pump.

Is the pump able to draw enough through the 5u filter? I imagine this would gain some extra pressure across the membrane.

That's a great question. I just called Aquatec today and spoke with one of their techs about the 8800 series. He said they don't spec the in feed vacuum or suction capability but should have around 6 feet of head. I will be doing a gravity feed system and want the filter before for two reasons, first most of the 5u filters are not designed for 125-160psi, and secondly I didn't want to place a strainer in front of the pump to protect it. His advised testing it to see if it would work. Has anyone else here tested with the 8851/8852?

I've seen a lot of questions regarding parallel vs series and the results are all over the place. The RO Bucket kit (http://www.therobucket.com/pricing.htm) seems to be using 400GPD in parallel, while only reducing sap by 50% water in a single pass. This would put 1.5% sugar to 3% sugar. I'd rather a system run longer and increase to 6-8%. I assume series is essentially like making multiple passes through the RO, except the pressure will drop across each membrane.

What pump would be suggested for the parallel system? What does the RO bucket (RB15-KIT) use for a pump? The 8800 is too small.
https://preview.ibb.co/kbQwDH/RO_System_Design_Parallel.png (https://ibb.co/dnTu0x)

Is the series better for the membranes and concentration? Is the only negative slower flow rate?
https://preview.ibb.co/bE63tH/RO_System_Design_Series.png (https://ibb.co/fUjpYH)

[hags]

I've seen a lot of questions regarding parallel vs series and the results are all over the place. The RO Bucket kit (http://www.therobucket.com/pricing.htm) seems to be using 400GPD in parallel, while only reducing sap by 50% water in a single pass. This would put 1.5% sugar to 3% sugar. I'd rather a system run longer and increase to 6-8%. I assume series is essentially like making multiple passes through the RO, except the pressure will drop across each membrane.
Looking at the math:

Using the 150 GPD membrane your average permeate flow is .104 GPM. 150 GPD / 24 Hours / 60 Minutes = .104 GPM
Since hodorskib is pressurizing the system to produce 10 GPH permeate or .167 GPM, he's above the membrane's .104 GPM permeate flow, so some membrane fouling will occur.
The membrane would be better off if the permeate flow was matched to the membrane's average flow, or if output was closer to 6 gallons of permeate per hour.
.104 GPM x 60 minutes = 6.24 GPH. So to lengthen the life of the membrane pressure should be adjusted to match the membrane's average permeate flow.

The other issue with pressurizing the system is membrane recovery. Membrane recovery is the ratio of permeate flow to feed flow.
The membrane should retain a 10-15% recovery to avoid fouling.
So hodorskib runs 12 GPH via the pressurized system which is .2 GPM and his 150 GPD membrane have an average flow of .104 GPM
.104 GPM / .2 GPM = .52, or 52% membrane recovery. This high recovery%, due to the pump only being able to supply 12 GPH when pressurized, leads to membrane fouling.

In theory, running the system as hodorskib has, you should use a 250 GPD membrane at minimum since it's permeate flow is .174 GPM and above the .167 GPM the system is outputting. This of course makes the recovery percentage go up, which can only be corrected by using a pump that can deliver a higher feed rate.

A 50 GPD membrane would correct the high recovery percentage of the system since it's average flow is .035 GPM.
.035 GPM / .2 GPM = .175 or 17.5% membrane recovery. A bit above the recommended 15% recovery, but maybe tolerable.
The downfall of course is .035 GPM is only 2.1 GPH of permeate and 9.9 GPH concentrate which is a complete reverse of his results.

Using the 4 or 5 membranes in series as designed and flushing / cleaning the system relatively often compared to the gallons processed is likely the reasons the membranes have survived.

When you look at the series vs. parallel setups you want to keep this in mind. The 150 GPD membrane has an average permeate flow of .104 GPM. The 150 GPD membranes in series stay at .104 GPM, since you're just adding more surface area via the series and feeding the next membrane from the previous one. In parallel, the added membranes increase the average GPM flow because each membrane is separate from the others, so four 150 GPD membranes in parallel equal 4 x .104 GPM or .416 GPM. You can see that using the system in parallel and not increasing the pumps output is highly detrimental to the recovery% .416 / .2 = 2.08 or 208% recovery. So I'm not sure how long those (3) 400 GPD membranes are going to last in the ROBucket parallel setup. 400 GPD membrane is .278 GPM average permeate flow X 3 membranes in parallel is .834 GPM average. Since they run 20 GPH or .334 GPM their recovery% is .834 / .334 = 2.50 or 250% recovery!! It should be interesting to see how long those membranes last.

hags

[carls47807]

Great info hags. Indeed, the membranes are getting worked in parallel.

It is important to remember that a 400gpd tfw membrane is only rated at 25% capacity at 32f. A 400gpd membrane should flow 100gpd of water, or .07gpm. 3 should give .21gpm. If you produce 12 gallons of water per hour that comes out to .2 gallons per minute which gives you 100% recovery.

Membrane fouling from sugar solutions has been found to be easily removed by frequent permeate rinses. It isn't ionic, and doesn't stick to the membranes very well.

The aquatec 8855 pairs well with 2 400gpd membranes (it lies somewhere between a 300 and 400gpd pump).

Carl

[hags]

That's a great question. I just called Aquatec today and spoke with one of their techs about the 8800 series. He said they don't spec the in feed vacuum or suction capability but should have around 6 feet of head. I will be doing a gravity feed system and want the filter before for two reasons, first most of the 5u filters are not designed for 125-160psi, and secondly I didn't want to place a strainer in front of the pump to protect it. His advised testing it to see if it would work. Has anyone else here tested with the 8851/8852?

I would agree the 5u filter should not be subject to 125 psi and before the booster pump is probably better. Gravity feed should create some feed pressure, depending on the setup, or a cheap low pressure inlet pump could be added. Most of the booster pumps have an inlet pressure max. of 30 psi. Flojet makes a 1GPM, 25 psi water pump for RVs. Since the pressurized system is only producing 12 GPH output your low pressure feed pump would always stay ahead.

hags

[eustis22]

now my hairs hurt

[carls47807]

An aquatec 8800 will easily self prime through a 5 micron filter. When it doesn't you'll know it needs to be changed.

The 125psi really isn't a problem on the filter. Unless it is entirely plugged the filter is actually seeing very little pressure differential (125 in and 125 out). They can handle a 80psi pressure differential, and if you had that you wouldn't have enough pressure to produce any permeate so you would have replaced it long ago.

The filters are wound to have inlet pressure, not suction. As they get plugged they squeeze tighter to decrease the probability of particles getting through. If you suck through them they probably wouldn't perform the same and you could lose your 5 micron absolute filtering capabilities. Plugged filters collapse under suction but hold their shape under pressure.

[hodorskib]

hags - you are correct on everything you said. I do push the membranes harder than is recommended. My family and my job commitments allow me only a few hours a day to collect and boil so I try and make the most of them. Over the past 6 years running the system the membranes can last between 2-3 years with flushing and washing on a regular basis. With that said you can purchase the membranes for under 25 dollars each which means 150 dollars every two years to save 75-80% on my boiling time and fuel costs is well worth it for me. I am running two setups this year to see how they compare one:
6 - 150gpd membranes in series as I have for the past two years
the second is:
3 - 400gpd membranes in series

After today I will have processed over 1,000 gallons of sap (averaging 1.2% sugar) to 7.5-8% and have found that they are about equal. I also test the permeate with a digital brix meter during each run and it always registers .01 or .00. The 6 membrane system seems to be doing a little better though. After each run I flush with permeate for about 10 minutes change the water filter and then do a warm wash cycle using RO soap (ph 11 - which is what the membranes are rated for) for about an hour. Then I flush with permeate for at least another hour (testing with a ph meter to make sure the ph level is the same as the permeate). This has kept both systems running as the first day I turned them on. At the end of the season I will will do a wash cycle and then a cycle with citric acid and flush for several hours then store them in a pvc holder with the preservative. If the weather holds I should process between 2,500 and 3,000 gallons of sap through them this year.

The concept behind this system is to provide an economical way for the backyard producer to use and benefit from an RO that they can put together themselves I hope this information has been helpful.

[hags]

Hey hodorskib,

Thanks for the reply and you have done an awesome job! Way above the call of duty to bring all this to the community and answer questions and in testing new ideas. This is the part of homemade equipment and maple syrup processing that I like most. I've run some new numbers and I think I see why the (3) 400 GPD membranes are possibly fouling. Now that I have the info. on your (6) 150 GPD setup I'll probably go back and run the numbers on that too. Using the information from Carl and re-thinking the process I can see why your original system has worked so well.

Thanks so much for sticking with it for 6 years! hags

[hags]

Here's a chart to decipher hodorskib. It looks like your current setup using (5) 150 GPD membranes is most efficient and easiest on the membranes at the 6:1 reduction you're currently running. At super cold sap you're a bit short of membranes if your using 6, but as the sap warms up, 4 to 5 membranes is plenty.
Note what happens when using the 400 GPD membranes and why you may be having issues with that setup.

I'm not sure why the chart is so small, but it's bigger if you click on it.

17967

[jdircksen]

Great info hags. Indeed, the membranes are getting worked in parallel.

It is important to remember that a 400gpd tfw membrane is only rated at 25% capacity at 32f. A 400gpd membrane should flow 100gpd of water, or .07gpm. 3 should give .21gpm. If you produce 12 gallons of water per hour that comes out to .2 gallons per minute which gives you 100% recovery.

Membrane fouling from sugar solutions has been found to be easily removed by frequent permeate rinses. It isn't ionic, and doesn't stick to the membranes very well.

The aquatec 8855 pairs well with 2 400gpd membranes (it lies somewhere between a 300 and 400gpd pump).

Carl

How would I know if my membranes are fouled?
I made a bad batch of syrup yesterday and I think possibly my RO is to blame. We had a warm spell and the trees stopped flowing sap for about 10 days. I ran the RO once during those 10 days to flush it. I thought my season was over but the sap started flowing again. Yesterday's batch went through the RO and while boiling it smelled off. It tastes weird too. I don't know how to describe it.

Today I'm boiling again except not using the RO. So far during the boil I don't smell anything funky. It seems pretty normal to me.

So....how do I clean my RO? I did notice yesterday that when I ran it, it stayed at 60psi for the first 5-10 gallons of sap. Then it went up to 100psi which is where it usually is.

[jwith]

6 - 150gpd membranes in series as I have for the past two years
the second is:
3 - 400gpd membranes in series


hodorskib, Thanks for all the helpful information, developmentand testing of different rigs. After all the feedback I decided to go with that 5-150 GPD in series over the 400GPD series or parallel. After looking over hags numbers and running my own I think for the pump I have it is much better suited for 150GPD. It will also operate closer to the membrane performance specifications. Plus, I'd prefer to run the system longer and have a higher concentration, than to run it fast and have to cycle it multiple times.


Here's a chart to decipher hodorskib. It looks like your current setup using (5) 150 GPD membranes is most efficient and easiest on the membranes at the 6:1 reduction you're currently running. At super cold sap you're a bit short of membranes if your using 6, but as the sap warms up, 4 to 5 membranes is plenty.
Note what happens when using the 400 GPD membranes and why you may be having issues with that setup.

hags, thanks for your analysis. This was helpful in sizing my system.

I'm sure you were just doing a first order analysis, but it appears you are assuming equal permeate, which assumes equal pressure and equal TDS over all membranes. I would think the TDS would go up as you go further down the series causing the osmotic pressure to rise and therefore cause different recovery over each membrane. Maybe this is not noticeable, I am no expert on RO systems by any means, just interested in the math and science behind it. Overall I realize a lot of these numbers are theoretical, especially since most of RO membranes are spec'd for NaCl not sugars. It would be interesting to calculate the actual recovery of each membrane.

[carls47807]

Hey jdircksen,

Was your syrup stringy?

Could be from nasties in your ro, or from old sap sitting around.

Was it a butterschothy flavor? It could have been diacetyl or metabolism off flavor. This can be a big problem when first introducing RO's. Because your sugar concentration is higher, if you don't start making larger batches the off flavor and smelly aromatics don't have time to reduce.

[Maple Time]

I just put together one of these systems and have a couple small leaks. I’m just wondering how to empty the system of water, can I just run the pump without anything on the input side to push it all out or do I just disconnect the fitting and let it spill out?

[hodorskib]

JDirksen: I posted this a couple of weeks ago on cleaning:

The soap I am using is from CDL - https://webstore.cdlusa.net/en/Catal...=022009001&ps= this is an organic product and was under 20 dollars so that is why I selected it.

The flushing and cleaning process I have been using this year:

After each time I run the RO I take 5 gallons of permeate in a bucket (1.5 - 2 gallons I put in a pot and bring to a boil then add it to the cold stuff - this gives me a temperature between 90-100 degrees *** don't go over 100 degrees) then run it through the system with the needle valve wide open and both the permeate and concentrate lines back in the bucket of warm water. I let this recirculate for at least an hour.

For cleaning - I have been doing after every two or three days of operation (this will increase as the season goes on with more bacteria building in the system) I take the same warm permeate but add the RO soap to it until it reaches a PH of 11. Then recirculate as above for 1-2 hours. It is amazing how this stuff works. For me I needed to about 1 level tablespoon of soap powder to achieve that level. So the 1kg container will be enough for me to do like 40 or 50 washings. Then I flush with permeate for at least an hour - this time letting it flow down the drain. If you don't have access to the soap right now I have heard back from some other folks who are using similar systems using 2 or 3 quarts of hydrogen peroxide instead and getting good results as well.

I have processed 400 gallons of sap this week and it seems to be working well. Last season as things went along the performance of my membranes deteriorated which is why I am trying the ro soap this year. I have also checked with the manufacturer specs on my membranes and 11ph is the max level.

I will be posting everything to my website at the end of the season to make sure it all works out - but there seems to be enough interest to put out what I am trying now.

[hodorskib]

MapleTime: you can shut off the feed and let the pump push what it can - only takes a few seconds but there is really no way of purging the system without letting it drain out of each housing.

[Maple Time]

Ok thanks.

[DaveB]

I have a question about membrane storage. I know that they can't freeze and I don't have a heated sugar house so I'm trying to think of options. I've built a system with three 400gpd membranes and one thought I has is can I remove the membranes from the housings and place them in a plastic bag and put them in my refrigerator to keep them cool and moist and just leave the rest of the system at the sugar house or do I need to bring the whole thing in? I can do that but I'm just wondering about options.

[eustis22]

ok, I suspect my shurflo 4008 isn;t robust enough for hodors model. I could only manage 10 PSI on my initial try. I didn;t even bother to open the needle valve up. I ordered an Aquatec for this. I ran about a gallon thru the membranes. DO I need to clean them before my next attempt?

Also, I was just sucking from a 5 gal bucket for my testing.....do I need any kind of head tank pressure?

[hodorskib]

Eustis:
Did you test with sap or water? If just water you won't build that much pressure. Yes you want to flush the membranes for about a half an hour or more to get them wet and to flush any funk that may be on them - even though they are new. Sorry I have never used any other pump can't help with that.

[hodorskib]

Dave:
I have heard of some people making a box out of 2" insulation foam board and putting an old style light bulb inside and leave it on. It will generate enough heat to keep from freezing from what I have been told. I would not let the membranes, water filter housing or pump freeze.

[eustis22]

I tested with sap..prolly 1.5%. Another thing..I am unclear on the position of the needle valve at the start of things...all the way open or all the way closed until the pressure buillds?

[hodorskib]

Needle valve should be open when you start and then start closing this should build pressure and force things through the membranes.

[Greenthumb]

Speaking of the needle valves for these homemade ro’s. Do you want the needle valve fairly close to the unit or is it ok at the end of the tube that feeds the ro sap.

[wobbletop]

Speaking of the needle valves for these homemade ro’s. Do you want the needle valve fairly close to the unit or is it ok at the end of the tube that feeds the ro sap.

It should be in the concentrate output line.

[Greenthumb]

It should be in the concentrate output line.

I know that but I guess what I meant was is there a advantage to having the valve close to the last membrane and the longer side to the collection tank vs the tube coming out and the valve at the end of the discharge tube.

[wobbletop]

Ok, I just didn't want other people to be confused.

At the flow rates these normally operate at, there shouldn't be a large pressure drop through the hose, so wherever is most convenient for you would be best.

[seanmacc]

I have a question about membrane storage. I know that they can't freeze and I don't have a heated sugar house so I'm trying to think of options. I've built a system with three 400gpd membranes and one thought I has is can I remove the membranes from the housings and place them in a plastic bag and put them in my refrigerator to keep them cool and moist and just leave the rest of the system at the sugar house or do I need to bring the whole thing in? I can do that but I'm just wondering about options.

DaveB,

This is how I built mine (video below)- It's strapped on to a small hand dolly. I don't remove the membranes. I store mine in our mudroom which stays at around 43 degrees and make sure that I perform the 20-30 gallon permeate cleaning before and after processing. Last year, I wheeled it into the house each night and left it by the door.


https://youtu.be/kMCmam8-UO0

[CaptT820]

I need help with my homemade RO. I am almost certain that I hooked everything up correctly, but I could be wrong. When I began to run water through it on the initial run to clean the membranes I started to build pressure up to about 40 psi, so I shut it off. I disconnected my needle valve to eliminate that as a possible problem and ran it again. It again built up pressure to 25 psi when just running water. I then removed these little blue clips form the tubing connections to the membrane housing that I thought were locking tabs, turns out they were creating a blockage with the tubing and building pressure. Once removed, the pressure went to zero. I reattached the needle valve, but could not get the pressure to zero, it stays at around 45psi. I am assuming I need a new valve? Anyone have a valve setup that they really like?
Just want to help others with my experience.

Thanks

[to100]

What I do is open condensate needle valve 100% and let run and get air out of system then start to close it and force out air in permeate side then adjust to get equal flow rate for 50/50 flow. I have 2 half pint jars in both buckets to see which is faster and fine tune. Save those blue clips that help seal John Guest fittings. Be careful where you put these when you want disconnect a hose, I PUT them back on fitting right away. I almost lost mine and looked at hardware stores NOT.
GOOGLE of a bag of 25 or more.

I think that if you are using well water for flushing, there will not be any pressure since the is nothing to squeeze out.

I am new to RO’s this year and have used it about 8 times.

If I am wrong please let me know so I can understand better.
Thanks

[CaptT820]

To100 thanks for the information. What kind of needle valve are you using? I have a standard 1/4" brass needle valve, but it seems to restrict the flow too much. I ran the system with well water to flush w/o the needle valve and no pressure. I attached the needle valve in the same setup with the valve wide open and it builds pressure to about 45 psi. I am going to try another type of valve (John Guest Poly, push connect) to see if that helps matters. The valve should obviously close all the way or be open all the way to allow full flow. I just think that the needle is too restrictive without some type of regulator on the pump speed.

Thanks

[to100]

Mine is a John Guest type push on. Go to Bucket site there is a video on needle valve. Use “therobucket”

[hodorskib]

You may have over tightened the compression fittings on the needle valve causing the tubing to compress. Not a big deal you can get new ferrules and reinstall.

[CaptT820]

I got the John Guest type, worked much better for me. Thanks.
Does anyone out there use a gallon counter with their homemade RO? I want to know how many gallons I am running through the system so I can keep track of when to change the 5 micron filter. If you are running a counter, what type is it, and do you like it?

Thanks

[to100]

Where do you set up ro? How much storage for perm and cond= sap. How do you add cond to arch?
I am smaller so I try to keep track of gallons taken out to preheater. Each run is different how I set up to try figure out what works best. All depends how you meter your needle valve.
I am more interested how much syrup. I am going to try run sap into 35 gallon leg tank and feed directly off valve on tank to ro. I will either carry couple gallons at a time or set up pump to send it up to arch. My average run is mid 20s and on a long day I may have 30 over night. I have 2 five gallon buckets I can connect with 5/16 tube so overflows to the other, I have yet to try. Good luck once it warms up.

[eustis22]

Can I use well water to flush my membranes?

[hodorskib]

yes well water should be ok make sure you have a 5 micron water filter installed in case you have any iron or sediments in your water

[eustis22]

I do have the 5 micron water filter. But I just noticed that I left the plastic wrapping on it in the canister when I was pre-washing the membranes. Yes, I knpw. Please stop looking at me like that. My next question is: am I supposed to peel everything off the membranes too?http://mapletrader.com/community/attachment.php?attachmentid=18218&stc=1

Note blue area

[hodorskib]

NOOOOO - leave the blue plastic and the labels on the RO membranes they are necessary. The only stupid questions are the ones not asked.

[eustis22]

thank you, Hodor

[eustis22]

so...I guess I'm ready to apply sap to this thing. What is the optimal outside temperature to do this? also, can someone explain the needle valve? What settings do what to which?

[wobbletop]

You don't want anything to freeze and break some plastic. The warmer the sap, the better the membrane works, but then warm concentrated sap spoils very quickly.

The needle value is to provide back pressure so it forces water through the membrane. Hodor's (sp?) website goes through the settings. I don't worry about it too much, just aim for equal concentrate and permeate.

[wobbletop]

I have a question about using the recirculate method...

Whats happens if you just leave it running and concentrating for a long time? There is a maximum sugar content the sap will reach (say 8%) but what happens if you keep going?

Does the permeate stop running? Or does the membrane start passing sugar and you lose efficiencies?

[hodorskib]

I have only managed to get to 12% by recirculating however, two things happened:
1. The system slowed way down
2. The membranes clogged to the point it took a very long time to clean and recover
3. I have also heard from others that the membranes will start passing sugar as well - I have never experienced that though

I try not to go above 8.5-9% it is not worth the hassle of the extended cleaning.

[Milton]

If you are worried about freezing, just recirculate. I ran mine in an unheated garage overnight with temps down to 20. I recirculated but setup a shoplight on the ro just on case. After running it this way overnight, I noticed that the residual ice on my feed tank was gone. I am assuming that the pump probably warms the sap a little as it runs through. The shoplights may have helped a bit too. I just would not let sit in freezing temps when not circulating.

[Milton]

Hodor thanks for all the detailed information. I read your site and logs for production. I'm really amazed at how much you are making with the ro and small evaporator. I'm thinking of going a bit bigger next year. Do you think a 2x4 continuous flow pan would match this setup?

Thanks

[hodorskib]

As I have said previously this year I have been very diligent about keeping the membranes as clean as possible. If your sap is usually 2% you should be able to process 150-175 gallons a day to 7.5-8% but that would be the maximum with this little RO. It is really designed for around 100 taps if you plan on processing and boiling daily. If not I would look at some of the other threads and build something a little bigger.

[eustis22]

ok then,,,virgin no more...I went from approx 2% to approx 4% over 25 gallons at 37 deg sap. My psi was about 125 PSI. what could be done to increase that 4%?

[edit] I closed the valve a little and psi = 140 and 6% sap.

Is there a max psi?

[Milton]

How many and what size membranes do you have? That will influence amount of water removed.

[eustis22]

per the authors instructions I have 4 150 gpd membranes

[hodorskib]

With the 4 membranes 6% and 140psi is a good number. Remember you just removed 2/3rds of the water and now are at 14:1. Congratulations!

[CaptT820]

Hodorskib-
How often do you flush the RO system? I have the same homemade system (1st year using it) and I found that I can run sap at ~100psi and get 6-7%. I have been flushing the system clean every drum that I run through (~60 gallons) and the performance seems to be consistent. I change the 5 micron filter for every drum. Do you do something different?

Thanks

[hodorskib]

The cleaner you keep the membranes the better the performance. I have been using an RO soap this year and doing a wash after each run and after 4 weeks and over 2,000 gallons of sap the system is running as well as the first day. I posted this information to my website.

[CaptT820]

I guess I meant how many gallons of sap do you run through per run before you clean it and/or change the 5 micron filter?

[hodorskib]

My normal runs are between 90-140 gallons so I replace after each run. However, if your sap is very clean and clear you can go two runs before replacing.

[Cedar Eater]

I've seen half size filters and housings that look just like the 10" Pentek except they are 5" instead of 10". Five micron filters are available and both the filters and the housings are a little cheaper. I would assume they are good for half as many gallons of filtering, so how many gallons are the 10" filters typically good for?

[eustis22]

ok, I have assembled my end of season wash materials. its been a couple weeks since my last RO and all I did after that last one was rinse out with 15 gals of permeate.....am I still ok w/r/t the membranes to do the soap/acid wash tonight? do I need to do BOTH soap and acid if I have no sap left to test thruput with?

[jdircksen]

I can't answer your question but can you post the instructions for the soap and acid wash? I need to do something because my membranes and prefilter canister smell really funky after sitting for 4 weeks.

[eustis22]

https://sites.google.com/site/mattatuckmadnessmaplesyrup/cleaning-ro-membranes

[MDR Maple]

I have been lurking here for a few weeks and grateful to all who shared their experience with their small scale RO builds. I have a barrel evaporator and RO Bucket (RB10). The evaporator can make about 7-8 gph in ideal conditions and the RO Bucket performed pretty well this season. It produced about 5 gph concentrate and 5 gph permeate with a doubling of the sap concentration from approximately 2.5% to 5%. My RO bucket has the Aquetec 8855 pump, a filter and 2 400 gpd membranes in parallel. The bucket made access for maintenance difficult, so I plan to mount it to a board.

I've read this very long thread frontwards and backwards but haven't seen anyone who has shared an idea like the following:

I'm considering a concept for modifying the RO system.

The concept is to modify the RO to make 8% concentrate at 7.5 gph so I can RO right into the pan while boiling. Basically, I'd like to match the RO concentrate production rate to the evaporator boil rate to the extent possible. The unique aspect to this concept is to use a point of use ultra low flow point of use water heater (http://www.stiebel-eltron-usa.com/sites/default/files/pdf/tech-specs-mini-mini-e.pdf) before the pump, but after the filter. The filter, heater and pump will have a flooded suction. This water heater can increase the sap temperature by about 40 degrees F and I'm hoping to increase the RO flowrate and concentration compared to my current setup to make about 7.5 gph at 8% concentrate right into the pan.


Do any RO systems heat the sap to improve RO efficiency?

Any comments regarding this concept modification would be appreciated.

[mol1jb]

I have been lurking here for a few weeks and grateful to all who shared their experience with their small scale RO builds. I have a barrel evaporator and RO Bucket (RB10). The evaporator can make about 7-8 gph in ideal conditions and the RO Bucket performed pretty well this season. It produced about 5 gph concentrate and 5 gph permeate with a doubling of the sap concentration from approximately 2.5% to 5%. My RO bucket has the Aquetec 8855 pump, a filter and 2 400 gpd membranes in parallel. The bucket made access for maintenance difficult, so I plan to mount it to a board.

I've read this very long thread frontwards and backwards but haven't seen anyone who has shared an idea like the following:

I'm considering a concept for modifying the RO system.

The concept is to modify the RO to make 8% concentrate at 7.5 gph so I can RO right into the pan while boiling. Basically, I'd like to match the RO concentrate production rate to the evaporator boil rate to the extent possible. The unique aspect to this concept is to use a point of use ultra low flow point of use water heater (http://www.stiebel-eltron-usa.com/sites/default/files/pdf/tech-specs-mini-mini-e.pdf) before the pump, but after the filter. The filter, heater and pump will have a flooded suction. This water heater can increase the sap temperature by about 40 degrees F and I'm hoping to increase the RO flowrate and concentration compared to my current setup to make about 7.5 gph at 8% concentrate right into the pan.


Do any RO systems heat the sap to improve RO efficiency?

Any comments regarding this concept modification would be appreciated.

I have read quite a bit in the last few months in preparation of getting a RO next season and have never heard of heating sap before ROed. In your application it should work fine since it is going right into the evap but in general even after sap is ROed you want it as low temp as possible before it heads into the evaporator to keep the sap as good as quality as possible.

[SDdave]

I have been lurking here for a few weeks and grateful to all who shared their experience with their small scale RO builds. I have a barrel evaporator and RO Bucket (RB10). The evaporator can make about 7-8 gph in ideal conditions and the RO Bucket performed pretty well this season. It produced about 5 gph concentrate and 5 gph permeate with a doubling of the sap concentration from approximately 2.5% to 5%. My RO bucket has the Aquetec 8855 pump, a filter and 2 400 gpd membranes in parallel. The bucket made access for maintenance difficult, so I plan to mount it to a board.

I've read this very long thread frontwards and backwards but haven't seen anyone who has shared an idea like the following:

I'm considering a concept for modifying the RO system.

The concept is to modify the RO to make 8% concentrate at 7.5 gph so I can RO right into the pan while boiling. Basically, I'd like to match the RO concentrate production rate to the evaporator boil rate to the extent possible. The unique aspect to this concept is to use a point of use ultra low flow point of use water heater (http://www.stiebel-eltron-usa.com/sites/default/files/pdf/tech-specs-mini-mini-e.pdf) before the pump, but after the filter. The filter, heater and pump will have a flooded suction. This water heater can increase the sap temperature by about 40 degrees F and I'm hoping to increase the RO flowrate and concentration compared to my current setup to make about 7.5 gph at 8% concentrate right into the pan.


Do any RO systems heat the sap to improve RO efficiency?

Any comments regarding this concept modification would be appreciated.


I've had hodorkskib's RO system for 5 or 6 seasons now. The main thing to consider is that increasing to a higher concentration %, leads to a decrease in concentration gph. You can get to a higher gph if you would like, but consequently a lower %. This year I did just that, I sacrificed higher concentration % to match the evaporator. The RO did take out about 40 to 45% of the water and could have gotten more removed, but it still shortened the overall time of processing sap in the RO and evaporating.

The strive to get maximum output is very commendable, but are you able to get the working 150 PSI for the heater thingy? Are you ready for fouling of membranes from the increase of heated sap? Just a couple of items I saw, but maybe you have addressed that.

Keep us posted!

SDdave

[Msboucha]

Are you ready for fouling of membranes from the increase of heated sap?

I agree with SDdave. I started with an RB15 this year that I needed to heavily modify..we average 3.5 sugar before RO, so getting to 8 was very slow as built...taking 2 to 4 is easier than 3 to 6 or 4 to 8. At those concentrations, there was not enough flow/pressure. The calculations will tell you that warmer is more efficient, and it is, until your flow rate begins crashing because the membrane is fouling. Up your pressure and flow rate, but don't heat over 40. Heating too much too soon also just means more bacteria/increased fouling rate. I tried various temps of preheated sap and while intially appeared promising, only meant having to stop and flush the system at full speed to unplug them. 40 seems to work very well to reach 60% rejection in a single pass. Preheat your concentration just before evaporating. With the added flow/pressure we can get from 3.5 to 8 at 13gph (about 5.75 concentrate). We also moved membranes into series, before the pressure/flow upgrade which helped because with 3 400s in parallel you really need to satisfy 1200gpd flow when going high concentration in order to avoid fouling.

[to100]

Msboucha, how many taps are you at now? Are you still off the grid?
I only heat sap to 60 to 70 and same for flush, I guess I am lucky on membrane fouling but I try to dial into 50/50. Being small I have 5gallon buckets marked by gallons inside so I can see how close I am or if flow rate changes by the quarter hour of run time. Then I can stretch the time longer for checking. I will know next year since Carl says new membranes every 2 years. Time will tell. I have 1 1/2 % sap on average and have seen 4 to 5% concentrate but usually less.

[Msboucha]

We ran 24 taps last year and this year on buckets. This is the first year with the RO. It took me a few weeks to get it modified to where it was worth the running time/ouput. Being off-grid, I didn't want to run for hours on battery with low output, and I couldn't afford to leave it overnight and risk freezing, so I typically RO 35 gallon batches for a couple hours in the evening that is fed from a large extreme cooler (holds ice for days), with sap that I keep at air temp if it is cool or a jug of ice. I RO into another extreme cooler and add jugs of ice, which keeps the concentrate for a few days without issue, and boil when I have say 20gal concentrate at 8%. I installed in line flow meters on my system, and the concentrate one has a flow adjustment which replaced the original needle valve. So much easier than trying to measure all the time. I compared the meter rates with a measuring cup vs time and they are pretty spot on. Keep in mind that the concentrate has higher density, so if the float in the meter is the same as the permeate float, you are actually higher concentration than 50/50. I do my flush wide open after with my 40ish degree permeate. Usually about 10 gal. I have not seen any performance loss and I've put about 250gal sap through since getting it in mid March (not that much volume, but we've spent a lot of that time since then froze up with little sap flow). I also suck 1 gal of fresh well water through the system before I begin ROing after a shutdown the flush out any crud that might settle out of the membran/stale water. Also I would do membrane soap or peroxide wash at the end of the year. That will clean them better for storage and I expect greater than 2 year life. Others could chime in on that though.

[hodorskib]

I have updated the website here is the new address: https://sites.google.com/view/mattatuckmadnessmaplesyrup/home

[jcn055]

We ran 24 taps last year and this year on buckets. This is the first year with the RO. It took me a few weeks to get it modified to where it was worth the running time/ouput. Being off-grid, I didn't want to run for hours on battery with low output....
Msboucha
I am also off-grid. What pump are you using to process through your four 400gpd membranes?
I am finding a hard time locating a 24v DC Aquatec (8852-2J03-B594).
~Thank you

[Msboucha]

Msboucha
I am also off-grid. What pump are you using to process through your four 400gpd membranes?
I am finding a hard time locating a 24v DC Aquatec (8852-2J03-B594).
~Thank you

I'm using a 24vdc 1.3gpm Seaflo with adjustable pressure as a feed for a 400gpd boost pump. The seaflo cycles on/off based on the pressure cut-off and the booster stays constant. Not sure how long the Seaflo will last but it ran a season without issue.

[jdircksen]

Does anyone use Leader R/O Soap (Sodium Hydroxide) with hodorskib's setup? I see in his instructions that he uses a heaping tablespoon of CDL “Superflow Green”. I am trying to determine how much of the Leader R/O soap to use with mine.
Do I need some kind of pH meter? I see pH strips at drug stores but the range on them is only 4.5-9.0.

[Msboucha]

Jdircksen - it's not so much the soap or the quantity as it is getting the correct PH. You'll want to check the manufacturer recommended PH level for your membranes, which will dictate the amount of soap you use. The hardness or softness of your water will also influence the PH. They should tell you the temperature to wash at as well. You can grab a digital PH meter online for not too much, and calibrate it with the provided solution.

[jdircksen]

Jdircksen - it's not so much the soap or the quantity as it is getting the correct PH. You'll want to check the manufacturer recommended PH level for your membranes, which will dictate the amount of soap you use. The hardness or softness of your water will also influence the PH. They should tell you the temperature to wash at as well. You can grab a digital PH meter online for not too much, and calibrate it with the provided solution.

I have the 150gpd one that runs about $25 each on eBay: https://www.membrane-solutions.com/residential-ro-element.htm
Looking through the spec sheet shows this: pH Range of Feedwater during Continuous Operation: 3~10

so I imagine I should shoot for a pH of about 9?

[Msboucha]

I don't see it off hand on their spec sheet, but I think my membranes are the same (just branded under a different name but identical look and feel to the Membrane Solutions ones) and specifically give a chemical cleaning pH range of 2-12 (slightly higher than the continuous feed range of 3-10). For mine, I use the H2O bio soap, and it works out to be 2oz per 5 gal to get up to 11.75. My well water is about 8.25. I wash at the highest temp they are rated for which is 113F.

[carls47807]

JCN055 - the aquatec 8800 series uses a universal motor, it can actually run off of AC or DC. A 24V DC transformer rated at 5 amps will suffice in place of the 24Vac transformer.

[carls47807]

The RO Bucket has used two different membranes over the last two years. We were using the membrane solutions ones but have since sourced a higher quality, tighter wound 400gpd membrane (if you look at the ends of the two there is a clear difference). The newer ones we have sourced have a pH rating from 2-12 (most TFW membranes will). In addition to their pH parameters, they recommend flushing with 1% NaOH solution/.25% sodium dodecyl sulfate (which is what we make up in our preservative vials). You would then neutralize that solution if necessary to get the desired pH range (I have made a lot of solutions with a lot of different water sources and have never gotten over a pH of 12).

Msbouchard - do you have the "Jozzon" membranes or the older ones?

[hodorskib]

jdickson - you can use ph strips or pick up a ph meter I found one on Amazon.com for under 15 dollars:
https://www.amazon.com/Drinking-Aquariums-Hydroponics-Resolution-Measuring/dp/B07LG88DS2/ref=sr_1_1_sspa?ie=UTF8&qid=1546955249&sr=8-1-spons&keywords=ph+meter&psc=1
works well and as for the type of soap you use as already said it is about the ph level. I chose CDL because it was organic, reasonable priced and I was able to get it locally. It is basically food grade lye. Make sure you use warm permeate or chlorine free water (a tip from a friend who services aquariums - if you use chlorinated water, like I do, fill up a barrel and let it sit for a few days the chlorine will dissipate). Then add a teaspoon at a time until you reach the desired level. Also, take a measurement of the ph of the permeate or water you will be using it will be helpful when rinsing/ flushing your membranes after a soap wash. When the ph levels return to normal you know that all the soap has been removed - for me it takes about 30-40 minutes but do an hour flush to be safe.

[Msboucha]

Msbouchard - do you have the "Jozzon" membranes or the older ones?

Hi Carl, they are the Jozzon membranes. I did add a 4th membrane for 2019 which is membrane solutions, but didn't pick up on the winding being different since the others are still in their storage vessel.

[Andrew Franklin]

In the interest of not posting repetitive questions I just re-scanned this entire thread, and I don't think I've seen a question like this addressed. I built a copy of your initial system a couple of years ago, with an aquatec 8855 pump, 4 150 membranes, and then bought 4 250 membranes last year when I saw them for a good price, but didn't use them as the season was about over. I just priced out a new aquatec 8855 pump, pressure gauge, and all the rest to create 2 systems and it comes to about $215. I see I can buy a procon 15 - 125 gph pump with motor with up to 175 psi for $180. Question...should I skip the 2 system setup and go with the procon? Will it give adequate flow and pressure for 8 membranes at the above capacity? I have to admit there was one flow rate/recovery chart that went beyond my paygrade, so if that explained it I apologize. Just wondering what the procon can run with 4 150 and 4 gpd membranes - all of them, or do I need to scale back (or can I scale up??) Thanks... you and all the contributors here have saved so many people so many hours by sharing what you've done with us.

[hodorskib]

I know someone who is using a procon pump with 4 - 400gpd membranes and it can easily handle more - depends on what model procon pump and what sized motor. However, if you are going to that size pump you might want to just go with a 4 x 40" membrane and be done playing with these small residential membranes and would be more sized to the number of taps you have. Comes down to $ and the fact you already have 8 membranes.

[Andrew Franklin]

Thanks much...that answered my question about capacity of the procon. I'll do some pricing comparison. Thanks again!

[metalhead62]

andrew i am with hobs the procon pump will handle what you have and more if you can return the filters then maybe move to the 4x40 (filter and vessel about 400$) if not run all the filters you have and when you need to replace them go to the 4x40 you will probably need some flow gauges and a few misc items you may or may not have with the smaller setup

[Andrew Franklin]

andrew i am with hobs the procon pump will handle what you have and more if you can return the filters then maybe move to the 4x40 (filter and vessel about 400$) if not run all the filters you have and when you need to replace them go to the 4x40 you will probably need some flow gauges and a few misc items you may or may not have with the smaller setup

Metalhead, you are both right, but I did a pre rinse through the new membranes thinking I would need them so I can't return. And to complicate things, I JUST got an out of the blue purchase offer on my 12 acres of maples on the lake (although they love the syrup and say I can keep tapping...but who knows).


That has me thinking to max out what I have until I know how things go with the buyers before upgrading.

So another question to you patient folks...

What is the capacity of my current 8855 aquatec pump, if I use a well head pump in front of it using any mix of my 4 150 gpd and 4 250 gpd membranes? That would just leave me needing to buy some new cartridges and I'd be set.

Thanks in advance for your help!

[hodorskib]

Andrew: The Aquatech pump is 1200 gallons per day (however, that is with no back pressure just free flowing). I have successfully run 3 x 400 gpd membranes with my pump and 6 x 150 gpd beyond that I have found there is no difference and the last membranes do nothing. Hope this helps.

[Andrew Franklin]

Andrew: The Aquatech pump is 1200 gallons per day (however, that is with no back pressure just free flowing). I have successfully run 3 x 400 gpd membranes with my pump and 6 x 150 gpd beyond that I have found there is no difference and the last membranes do nothing. Hope this helps.Exactly what I was looking for...thanks again!

[MDR Maple]

Many thanks to Hodorskib and others for sharing their experience with small scale RO builds. Last year I used the RO Bucket (RB-10) with Aquatech 8855 and 2x400 gpd membranes in parallel with pretty good results overall. This year I decided to disassemble the Bucket and mount it to a board to ease access to the RO components. I often found myself chasing a small air leak in the tubing connections and had difficulty getting to the tubing connections to ensure they were fully seated. I'm hoping that the board mount will provide easier locating and fixing of leaks, or, even more so, I'm hoping I'll be able to assemble the tubing connections properly to prevent leaks. I also will add a another membrane to make it a 3x400 gpd kit and plumb it in series like the Hodorskib Build.


I have successfully run 3 x 400 gpd membranes with my pump and 6 x 150 gpd beyond that I have found there is no difference and the last membranes do nothing.

Hodorskib: I recall you indicated in a posting quite a ways back that you had planned to share the results of the 3 x 400 gpd system. I've searched these postings and your website but could not find it. I'm curious how the 3 x 400 gpd system performed compared to the 6 x 150 gpd.

[hodorskib]

MDR - sorry never posted the results from running both systems last year. The 6 x 150gpd system worked flawlessly I put about 2,000 gallons of sap through it over the course of the season. My sap was running around 1.3% and I was concentrating to around 7.5% and was processing about about 9-10 gallons per hour through the system. I was able to remove 84% of the water in a single pass. This was also the first year I was using RO soap instead of Hydrogen Peroxide. I did a wash after each run and found that there was no loss in performance over the entire season. If your sap is more around 2% I would only go with 5 membranes. My system with 3 x 400gpd membranes did not do as well. I had it plumbed with 3/8" tubing throughout and although was able to concentrate to the same level 7.5% but the rate of process was not as fast with only about 7-8 gallons per hour. However, I lent it to a friend who was swimming in sap and had him set it so that it was a 50 - 50 permeate to concentrate. This worked extremely well and allowed him to process between 250-300 gallons per day which was perfect for his needs. I think the larger membranes need a higher flow. As for mounting your system to a board it will make things a lot easier to work on. Last year I put mine together on casters which still allowed for easy access but took up less area and made it easier to move around. I will be posting pictures to my website sometime next week after I take it out of storage.
https://sites.google.com/view/mattatuckmadnessmaplesyrup/home

[sbedilion]

Quick question. Everything seems to be running good. Curious on what my pressure gauge should be reading. It’s currently at 80psi. Its my first time running this setup and I followed the plans to a T. Starting at 1%....coming out at 4%. Thanks in advance for any help.

[jdircksen]

Quick question. Everything seems to be running good. Curious on what my pressure gauge should be reading. It’s currently at 80psi. Its my first time running this setup and I followed the plans to a T. Starting at 1%....coming out at 4%. Thanks in advance for any help.

Mine usually runs around 85psi. That's with sap that is about 40*F and the needle valve set to give me 50% permeate and 50% concentrated sap. I usually have 2% going in and 4% coming out.
The pressure it runs at will change based on the temperature of your sap. If I remember from last year, warmer sap run at a lower pressure and colder sap ran higher than 85%.

[sbedilion]

Thanks jdircksen! Ran 50 gallons of 1% down to about 12-13 gallons of 4%. I'm now ready for some bigger runs next week. :)

[jdircksen]

how'd you get the 75% reduction? Do you recirculate the concentrated sap as it comes out or just have your needle valve set to give 75% permeate and 25% concentrate? how long does it take?

I did about 45 gallons of sap down to 22 gallons. it was 2% -> 4%. that took about 5.5 hours in a single pass. I have 3 of the 150gpd membranes.

[jdircksen]

and you might want to see if your pump is adjustable. I just saw this on hodorskib's website:

It is connected to an Aquatech 8800 booster pump. This pump is designed to boost and maintain 100 psi of pressure with little or no feed pressure. However, depending on what membranes you use you can actually increase the pump to match the maximum levels for your membranes. To do this you will want to rotate the small screw on the front of the pump clockwise up to one rotation. I found one full rotation put me slightly above 125 psi so I went with a little over a 3/4 turn and that put me just below 125ps.

[sbedilion]

how'd you get the 75% reduction? Do you recirculate the concentrated sap as it comes out or just have your needle valve set to give 75% permeate and 25% concentrate? how long does it take?

I did about 45 gallons of sap down to 22 gallons. it was 2% -> 4%. that took about 5.5 hours in a single pass. I have 3 of the 150gpd membranes.

I don't know. haha. My sap is seriously 1% or less. I have 4 of the 150gpd membranes. I was running at 85psi but it wasn't a 50/50 output. More like the 75%/25% you noted. I forgot to time how long it took...maybe 4-5 hours. Last season I made 10 gallons from 1% sap.....that's a LOT of driveway boiling time.

[MDR Maple]

MDR - sorry never posted the results from running both systems last year. The 6 x 150gpd system worked flawlessly I put about 2,000 gallons of sap through it over the course of the season. My sap was running around 1.3% and I was concentrating to around 7.5% and was processing about about 9-10 gallons per hour through the system. I was able to remove 84% of the water in a single pass. This was also the first year I was using RO soap instead of Hydrogen Peroxide. I did a wash after each run and found that there was no loss in performance over the entire season. If your sap is more around 2% I would only go with 5 membranes. My system with 3 x 400gpd membranes did not do as well. I had it plumbed with 3/8" tubing throughout and although was able to concentrate to the same level 7.5% but the rate of process was not as fast with only about 7-8 gallons per hour. However, I lent it to a friend who was swimming in sap and had him set it so that it was a 50 - 50 permeate to concentrate. This worked extremely well and allowed him to process between 250-300 gallons per day which was perfect for his needs. I think the larger membranes need a higher flow. As for mounting your system to a board it will make things a lot easier to work on. Last year I put mine together on casters which still allowed for easy access but took up less area and made it easier to move around. I will be posting pictures to my website sometime next week after I take it out of storage.
https://sites.google.com/view/mattatuckmadnessmaplesyrup/home

Thanks for replying.

[jdircksen]

Question...
When I'm doing the soap wash, how should I have the needle valve set? wide open or restricted like when I'm processing sap.
thank you

[to100]

Quick question. Everything seems to be running good. Curious on what my pressure gauge should be reading. It’s currently at 80psi. Its my first time running this setup and I followed the plans to a T. Starting at 1%....coming out at 4%. Thanks in advance for any help.

Did you measure how many gallons came out each tubing per minute?

Also check how the membranes are plumbed up, series or parallel?

Just a thought.

[bowhunter]

I would run the needle valve open so you maximize the flow across the membranes. This should improve the cleaning action. If you raise the pressure then a lot of the water will come through the membrane as permeate.

[eustis22]

how much permeate to do the post-wash rinse?

[hodorskib]

It takes me about 30 minutes to rinse after a soap wash. I like to have 50 gallons on hand but if I remember correctly it is about 35 gallons.

[jdircksen]

Help me understand how membranes work. Wouldn’t I want to do the soap wash and rinse with the valve restricted so that it pushes soapy water through the membranes? If I do it with the valve open then won’t the stuff I’m trying to clean out stay in the flaps of the membrane?

[hodorskib]

Your thinking is correct however with membranes the best way to wash/flush them is to create turbulence across the membrane this loosens everything and allows it to flow out. The holes in the membrane are only large enough to allow water molecules to pass through. Sugar molecules are too large and cannot pass through but sometimes will get stuck under pressure. By leaving the needle valve open the flow will loosen everything kind of like a pressure washer on your driveway washing away the dirt.. Hope this helps.

[jdircksen]

Your thinking is correct however with membranes the best way to wash/flush them is to create turbulence across the membrane this loosens everything and allows it to flow out. The holes in the membrane are only large enough to allow water molecules to pass through. Sugar molecules are too large and cannot pass through but sometimes will get stuck under pressure. By leaving the needle valve open the flow will loosen everything kind of like a pressure washer on your driveway washing away the dirt.. Hope this helps.

I was thinking that dirt got down inside the membrane, but if I'm understanding you correctly then the dirt just stays on top of the membrane (the outside) and the open valve flushes the dirt away.

[hodorskib]

If you think of a membrane like paper towels. The material is in a long sheet and there are millions of microscopic holes so small that only water molecules can fit through. Then it is rolled up and looks very similar to a roll of paper towels. There is a plastic cover placed on the outside and when pressure is applied the liquid is forced through all of these layers of the material. What goes through is pure water - permeate and what cannot pass through is concentrate. Here is short video that I have used to help my students understand the process - It is using salt water instead of sap but it is the same principal.
https://www.youtube.com/watch?v=4RDA_B_dRQ0

[Msboucha]

I also have a question with regards to the washing/rinsing - this will be my 2nd year with my homebuilt RO. During the season I do a permeate rinse after each day and then a rinse with our soft well water (I know some will say not to do use this, but our water is pretty good and honestly I think better than the permeate which might have a small amount of sugar in it) before each run or every other day when not running just to keep things fresh. I completed a soap wash with H20 Biomembrane at the end of the year and stored the membranes in a vessel of sodium solution. Just pulled them out and they were pretty good, slight odor - I probably could have used more solution or else changed it after 6 months. I ran a rinse and I'm now re-running a soap wash. Any benefit or harm/foul to leaving the soap in the RO/membranes until I am ready for first run this season and then rinsing it out before starting to concentrate? Would this help prevent bacteria growth before I run next time? Otherwise, my plan is to rinse out and then continue as if we were between runs, passing some clean water through it every other day until we start.

[Pokegama Pointe]

Great thread - appreciate everything. I’m jumping in on the RO bandwagon this year! With that, can any of you offer me some advice on the height placement of the pump? I’m reading some say it should be below the sap and watching videos where it is above the sap. In your opinions does it matter? Thanks for any advice you can offer.

[CaptT820]

Everybody who has never used a homemade RO will love having one. I cant thank Hodorskib enough for this idea/thread as it allows you to get a lot of time back doing regular life things.
I am also curious if someone could chime in on the steps to "reviving" the RO back to use after 10 months of storage. I stored them properly, but just want to make sure that I get the system going properly this year without any foul odors or any other contamination.

Thx

[hodorskib]

MsBoucha - I would not let the soap solution sit in the membranes - it is a cleaner not a preservative. Permeate or in your case well water is enough to keep them moist. You can always just run it for 10-15 minutes if you have no sap to run for several days.

Capt - just do a soap wash and then a good rinse and you should be good to go.

[Msboucha]

Thank you, hodorskib!

[eustis22]

Help!

Started the RO after the pre season wash/rinse and I have no (zero/zip/nada) concentrate coming out and my pressure is very low. What can I test to see if I messed up my membranes (preservative/was/rinse)?

[hodorskib]

eustis - have you closed the needle valve - this will create the back pressure that forces the water through the membranes. If you have please make sure you have it plumbed correctly. If not send me a PM.

[eustis22]

thanks. sent.

[eustis22]

good news...crisis over...seems that when SOMEBUNNY put his tubes back in after the offseason he switched the permeate and concentrate outflow lines. Idiot.

Anyways I will do a new soap wash/rinse during this cold snap. Thanks, Hodor!

[hodorskib]

I was no longer able to edit the old website so I needed to take it down. Here is a link to the new one: https://sites.google.com/view/mattatuckmadnessmaplesyrup/home

[eustis22]

So I did my first ROing of the season....compressed 100 gallons of 1.3% to 25 gallons of 5% at 135/140 psi over 6.5 hours. for some resaon, I was under the impression that, during the season, I only had to rinse between ROings unless I saw performance drop and THEN I would do a wash? That begs a second question, what counts as a performance drop? Lower concentate %? Lower flow rate?

also, is 5% a good number for the HodorBuild with my current sap %?

[bowhunter]

As the membranes foul you will get less permeate while operating at the same pressure. It get's more difficult for the water to permeate through the membrane from the concentrate side to the permeate side. A 20% drop in permeate flow would indicate that you need to clean the membrane. So when your membranes are clean you should measure the permeate flow at a given pressure, say 100 psi while running on water or permeate. It's important to do this at about the same temperature as temperature has a large impact on permeation rates. The clean permeate flow is your baseline for that pressure. During the season do the same measurement at the same pressure, say 100 psi, after you have rinsed the membranes to see if the performance has declined significantly (20%). If you let the performance drop too far you may not be able to recover the performance by cleaning. Others can answer your question about whether 5% sugar is good better than I, but the math seems right since you removed about 75% of the water. I also don't think you can get too much above 5% with 130 psi.

[jdircksen]

eustis22
Performance depends on several factors. Temperature is one. How many membranes and their flow rate is another. I only have 3 of the 150gpd membranes and get lower performance that what you reported. I usually see 2% sap go to 5%. At the end of the season I saw 1.75% go to 4%. Mine is processing about 8 gallons of sap an hour, giving me 4 gallons of concentrate. I tried once to squeeze the sap a bit more (66% permeate to 33% concentrate) but it was really slow, I let it run overnight for 6 hours and it was only processing 5gph of sap. It took the 2% sap up to 6% though.

next year I'll buy 2 more membranes since that seems to increase processing rates.

also, about the RO soap. I did it a few times during the season when the trees froze up and I knew the RO was going to sit. If I go more than 2-3 days between using it, it starts to smell. The pail of RO soap is going to last me forever so I don't mind using it during the season.

[eustis22]

I have 4 of the 150 GPD membranes in series. Would upgrading my membranes increase my concentrate %?

Measure. Measure how?

[hodorskib]

Over the past two years I have been running 6 membranes in series and have found that I am able to get an 8% concentrate starting from 1.5% sap in a single pass. If the sap is cold in the 30s about 8 gallons and hour through the system and above 40 8-10 gallons per hour. After each run I do a soap wash for about an hour- an hour and a half. This is has kept the system clean and running great. I just finished processing 2,000 gallons so far this season. Keep them clean and they will perform.

[Gardenfork]

Hi Hodorskib and all for sharing 22 pages of great info here. I just read through it all and Hodorskib's website. I have two questions and if they have already been answered please point me to the post, thx!

1. Temperature: I am north of Hodorskib in Colebrook, CT where it stays real cold. My sap is stored in my unheated garage. It seems the ideal temp for ROing sap is 40F. My sap is usually colder than that. Should i use a heater of some sort (an aquarium heater, inline heater, or stock tank heater might work) to raise the temp of the sap going through the RO to about 40F, or just deal with the reduced gal/hour with cold sap?

(I'm aware you don't want to heat up the sap too much due to mold growth)

2. New to all this, I bought 100GPD membranes instead of 150GPD membranes. I collect maybe 60 gallons per run, so I don't need to process large quantities overnight. Will the 100GPD membranes be OK? Will I be able to raise the sugar content as much as if I used 150GPD membranes?

Many thanks, Eric.

[deitzd]

Thank you Hodorskib. I built my 5 cartridge 150GPD series system over the winter and tried running it today. Was hoping to boil concentrate this afternoon. My raw sap is coming in at 4%. I adjusted the pressure until I had about 50/50 coming from both outputs and then measured my permeate and concentrate with a calibrated refractometer. It showed quite a bit of sugar from my permeate line. I verified the plumbing and then tried again, this time lowering the pressure to allow about 4:1 concentrate to permeate. Doubled checked the calibration of the refractometer and measured raw sap again at 4%. Sap from the concentrate line is at 4.2% and sap form the permeate line is at 3.8%.

When I received the cartridges I noticed that they had packed the membranes inside of the cartridges. They were pushed into the bottom of the cartridge and plastic packaging had folded around the o-rings. I just checked the o-rings on all 5 membranes and the o-rings look okay when they're wet but when I spin the membrane I can feel that some of the o-rings aren't perfectly smooth. I'm going to replace all 10 o-rings tomorrow.

Any other ideas?

[Msboucha]

deitzd-

Sounds like a plumbing issue or a bad membrane in the mix. I suppose it could be the o-rings and thats a pretty quick/easy fix if it is, but in the mean time, can you post a photo of your plumbing? I know you said you checked it, but it wouldn't be hard to accidentally plumb one of the lines wrong. Others have noted it on here before. Sometimes a second set of eyes helps.

[deitzd]

Here it is.
19901

[Msboucha]

Looks good as far as I can see. You could try bypassing the 4 additional membranes and add them back into series one at a time to see if one of them is bad. If you narrow it down to one that starts letting the sugar pass, check and see if It could also be a crack in the housing some how letting the two sides mix. I've had 3 housings blow pinholes in the bottom where it comes off the machine that forms them. I end up "welding" the hole with a red hot screw driver to plug it.

[deitzd]

Thanks much Msboucha. I'll replace the o-rings tomorrow and then try bypassing each membrane if necessary.

[carls47807]

It might be easier to run a separate permeate line from each ro housing. Test each permeate separately and isolate the contaminated one(s). It could be a poorly wound cartridge, or even a cracked housing.

I would suspect that your readings are within an acceptable margin of error for the instrument (meaning your permeate and concentrate are the same sugar concentration). Do you get any flow out of the permeate line BEFORE you apply any restriction? With those readings, I would think that a membrane is missing entirely, or a housing has a large internal crack. If one membrane is leaking you should still have a considerably higher concentrate sugar % than permeate.

Can you get the system to 100psi?

[deitzd]

Did some testing with well water this morning. At zero pressure there is some flow from the permeate line, about 10% so it's not plumbed backwards. With clear tubing at the bottom of each housing I could see flow (and bubbles) from the permeate side of all 5 of the housings. I also tested each individual housing and get a little bit of flow from the permeate side at zero pressure. With the whole system together the most I can get is 68 pounds of pressure on the gauge between the 5 micron filter and the first housing. This is with the screw on the pump head at max.

This system is in my basement and has never been subject to freezing temps so I don't suspect a cracked housing, although anything is possible. I'll replace all the o-rings this afternoon and give it another try.

Thanks for the great advice.

[Msboucha]

This system is in my basement and has never been subject to freezing temps so I don't suspect a cracked housing, although anything is possible.

Crack wise, I was thinking more of a manufacturing defect. After patching the first housing I had that sprung a leak, I ordered a spare in case it didn't hold. When the next one blew a pinhole in the same spot, I went to throw in the spare only to find it had the pinhole defect brand new out of the package. They are pretty cheap, so it really wouldn't surprise me.

[deitzd]

Crack wise, I was thinking more of a manufacturing defect. After patching the first housing I had that sprung a leak, I ordered a spare in case it didn't hold. When the next one blew a pinhole in the same spot, I went to throw in the spare only to find it had the pinhole defect brand new out of the package. They are pretty cheap, so it really wouldn't surprise me.

Would this defect be visible inside the housing?

[Msboucha]

Maybe, I was only able to identify the exact pinhole location the first time because it was misting under 150psi. It was right in the center of bottom of the housing where it comes off the form machine. It almost wasn't visible otherwise.

[hodorskib]

Don't worry about pressure when you are running water - most likely well under 100psi more likely around 60psi. You should also leave the needle valve wide open when flushing so there will be little to no pressure. As for sugar in your permeate. My refractometer has some issues with % under .5 do yourself a favor and take a quart to a half gallon of permeate and boil down to 25% let cool and then take a reading. If it is reading the same as your initial number you are not passing any sugar. Good luck.

[deitzd]

Well, I replaced all 10 of the o-rings and it seems to have made a little difference but not much. I'm still getting liquid from the permeate line at zero pressure. I checked each individual housing and I still get fast drips of liquid from the permeate side of all 5.

I loaded the system with sap and I can easily attain 100 psi between the 5 micron filter and the first housing (I didn't check this prior to changing the o-rings). I'm getting almost exactly 50/50 from each line at 90 lbs of pressure. I measured the concentrate at 5.2 Brix with the refractometer. The permeate is at 2.1 Brix.

I boiled 1/2 gallon of the permeate down to 16 ounces. By the time I was half done I could tell by sight and scent that there's plenty of sugar in it. I let it cool to a little over room temp and it measured at 8.6 Brix.
19914

I definitely have a problem here. What are my next steps? I did find a place where I can get 5 new housings for $47.42 shipped.

[deitzd]

BTW: I did lube the o-rings and the top gasket with a water based lube when reassembling.

[Msboucha]

How is the rubber seal around outer top of the membrane itself - you said something like they had wrapped them in plastic and shoved them in the housings? Is it maybe deformed a bit and letting sap by?

[deitzd]

Yeah, when they shipped them they put the membranes (which were wrapped in their plastic packaging) inside of the housing for shipping.

That rubber seal seems okay. I rubbed my fingers around them when I lubed them for reassembly and didn't notice any rough or flat spots.

I ordered 5 new housings. I hope that does it because the only thing to replace after that are the membranes.

Just a little more information: I ordered all of the supplies for this project last May so the membranes were stored that way for quite a while. I'd consider contacting the supplier but it was so long ago.

[Msboucha]

Grasping at straws here -- how did you do your initial flush? Pure water or sap? I read somewhere else on the forum that it was advised to use only water as using sap could cause the membranes to foul before they are even put to work. Elsewhere I've read that fouled membranes can pass sugar and need an acid wash to reset the pores in the membrane. Seems far fetched for what you have setup though.

[deitzd]

Last weekend (March 23) I used softened well water to make 110 gallons of permeate. I then removed the 5 micron filter and used membrane flush from RO Bucket for about 20 minutes and left it soak for the week. Then rinsed with the permeate replaced the 5 micron filter and started running sap.

[eustis22]

how did you soften the well water? I am out of permeate.

[GiffordHillGold]

What about letting each permeate line drain seperate, then boiling a sample from each. Possibly you have only one bad unit and can remove it from the system and replace when your new housings arrive. Good luck and keep us posted!

[carls47807]

Try recirculating 10 gallons of well water through the system for 30 minutes. Run it dry, and then process some sap. After 10 minutes of processing take a concentrate and permeate test.

What kind of membranes are you using (are they TFW RO or nano?). Maybe send the model number?

Sounds like a membrane issue. Perhaps the membrane flush isn't thoroughly rinsed out (you generally only need to use it when performance drops).

Test each permeate separately for sugar (with your refractometer) and see if it is a single membrane passing sugar or all of them.

I notice a majority of brand new membranes will pass up to .5% sugar. After 50 gallons of sap or a good permeate rinse, however, the number should drop to zero. Are you able to measure TDS levels in the permeate and sap (with a conductivity meter?).

A bad upper lip seal wouldn't cause an issue with permeate quality. It would cause a decrease in permeate quantity (sap wouldn't be forced through the membrane, it would leak past the seal and exit the concentrate discharge).

Good Luck!
~Carl

[deitzd]

how did you soften the well water? I am out of permeate.

My house has a water softener installed.

[hodorskib]

This sounds like a bad membrane and I would guess by that amount of sugar in the permeate that it is most likely your 2nd or 3rd one in series. Attach separate lines to each housing for your permeate - collect each one and test as was suggested earlier. This will isolate the bad one and take it out of the system.

[deitzd]

Try recirculating 10 gallons of well water through the system for 30 minutes. Run it dry, and then process some sap. After 10 minutes of processing take a concentrate and permeate test.

What kind of membranes are you using (are they TFW RO or nano?). Maybe send the model number?

Sounds like a membrane issue. Perhaps the membrane flush isn't thoroughly rinsed out (you generally only need to use it when performance drops).

Test each permeate separately for sugar (with your refractometer) and see if it is a single membrane passing sugar or all of them.

I notice a majority of brand new membranes will pass up to .5% sugar. After 50 gallons of sap or a good permeate rinse, however, the number should drop to zero. Are you able to measure TDS levels in the permeate and sap (with a conductivity meter?).



The membranes I'm using are Membrane Solutions ROULP-2012-150.

I can try your idea of running well water for 10 minutes and then test the sap after minutes. I don't have access to a conductivity meter.
I'll then try to run some sap through each of the 5 membranes 1 at a time and do the boil test.
This will have to wait until the weekend as I work full-time and I need to boil sap in the evenings.

I ordered 5 new housings and 5 new membranes (from 2 different suppliers). Those will be here on Thursday.
The new membranes are GE FX12M. If nothing else I'll have them for the future. Hopefully we can get the ones I have to work.

Thanks everyone. I'll keep you posted.

[wobbletop]

Just buy a cheap tds meter and you should be able to tell which one is bad very quickly. A lot faster than boiling.

[deitzd]

Nothing changed in my system except that the membranes soaked in RO preservative during the week.

Ran softened well water at no pressure 5 min to flush out soap. No pressure = 18.5 psi on the gauge between the 5 micron filter and the first housing and 0 psi on the gauge before the pressure controller on concentrate line. Does this indicate an issue?
Put 5 micron filter in and recirced softened well water at no pressure for 30 min.
Ran the system dry and removed water from the 5 micron filter housing and replaced with new filter.
Processed sap for ½ hour at 125 psi before the first housing with each line into 7 gallon buckets. (the needle jumps around 122-131) (steady 119 psi just before the pressure control on the concentrate line).
After ½ hour I had about 6.5 gallons in the permeate bucket and about 2 gallons in the concentrate bucket.
Raw sap: 2.6 brix
Concentrate: 7.9 brix
Permeate: 1.8 brix

Processed sap for another ½ hour at 100 psi before the first housing with each line into 7 gallon buckets. (the needle varies, not jumps around, 96-103) (steady 86.5 psi just before the pressure control on the concentrate line)
After ½ hour I had about 6 gallons in the permeate bucket and about 4 gallons in the concentrate bucket
Raw sap: 2.6 brix
Concentrate: 5.4 brix
Permeate: 1.8 brix

I’m going to run the system as is at 125 psi this afternoon to process and boil the sap I have. I’ll hold the permeate in tanks and recirc it later to rinse the system and possibly pull some of that sugar out. Tomorrow morning I’ll run sap to each housing to see if I can isolate if 1 is passing the sugar. I have 5 new housings and membranes here that I can swap out if necessary.

BTW: I checked around town for a TDS meter and couldn’t find one. My multimeter measures continuity down to 20M but with 2 probes you can’t hold them at a consistent distance from each other to get a constant reading.

[deitzd]

Boiled sap for 4 hours this afternoon with the RO feeding the head tank. I sure went through the sap compared to boiling raw. Started with the head tank full and only had to refill it once and only because I don't like running with it less than half full.

Pressure at the end of the run was the same as the start. I checked my permeate coming from the line at the end of the run and it was 1.5 brix. Boiled 1/2 gallon of that down to 16 ounces. Checked at room temp and got 5 Brix.

I'm now recircing my permeate through the RO to flush it and hopefully get some of that sugar back. I adjusted pressure so that I'm getting just a steady drip from the concentrate line (130 psi). I have the permeate line running back to the permeate barrels. After recircing for a couple hours I'll check the brix from each line and let you know. I'll run it like this overnight and then flush with permeate at low pressure in the morning.

I should have time tomorrow to test the brix coming from each individual housing.