RO output lacking

[canaanmaple]

Any suggestions on things to check on why the output of my RO would be slower than last year? (its a nextgen 180gph 2 4x40s) I could swear last year I was getting at least 150gph. Just ran it for first time this year and seems like I was only getting 100gph. (was stored with preservative, and rinsed with 200gal premeate before using) Did a rinse and recirculated warm water halfway through the day and didnt seem to improve the flow. It's concentrating just fine, not passing any sugar and pressure was good. Just getting 100gph proccessing it seems. Temps were just above freezing, so not sure if that is enough to make the output slower or if RO gph ratings are based on 50 degree sap?

any suggestions would be apreciated! :) thanks and have a sappy day!

[220 maple]

CanaanMaple,
Don’t know if Sugar Content changes flow rate, are your trees sweet like always or is it lower this year like mine?
Mark220maple

[ronintank]

I got 4 good years out of my first memtech 4 x 40 membrane. then on year 5 it just would not flow as good so i replaced last year and flow came back. i tried cleaning the old membrane through 2 full cleaning cycles and it didnt help.
i make around 40 gallons of syrup per year from trees that run around 1.5 percent sugar.

[canaanmaple]

CanaanMaple,
Don’t know if Sugar Content changes flow rate, are your trees sweet like always or is it lower this year like mine?
Mark220maple

out of 3 spots I get 1.7, 2.0 and 2.7 I also run the machine outside at close to freezing so I have learned cold sap can lower the performace by 30%
Just need a bigger unit I guess! :)

[Rselleck91]

Are you using soap on a wash cycle? Also acid wash? If you do t consider these filmtech membranes junk

[neil2fish]

Cold sap makes a HUGE difference on mine. Freezing sap is much slower than a 45-50 degree day. Thats why you benchmark at a specific temp. we benchmark w well water at 55 degrees so we can compare that from year to year

[Amber Gold]

Sap temp does make a big difference in throughput, especially sap near freezing.

The best thing to do is to do a benchmark test after each concentrate cycle. It'll monitor membrane performance and let you know when performance is falling off. It only takes a few extra minutes at the end of the night. I keep a spreadsheet log for the season. If you see performance going down, you can do a double wash to try to get it back up, or an acid wash if it's really dropping.

[RC Maple]

I've been struggling with this issue all season where it has never been an issue the previous four seasons. I always test the membranes before the season starts. Again, this year the numbers for the membrane performance were good. What I couldn't notice from doing the test was the time it took to run a given amount through. Processing seemed much slower when the season began. I could no longer build concentrate levels during a boil but was barely keeping up. I had new membranes on hand and swapped them out. Initially, a big difference! Now, I am back to the same slow rates. At 33 degrees and 40 degrees temperatures, I processed sap at 13 and 14 gal/hr. at 50 degrees, I processed sap at 20 gal/hr. Now, two weeks later, 20 gph at 50 degrees seems like a dream as I can't get over 14 gal/hr with even warmer temperatures and warmer sap. The flow coming out of the concentrate is anemic compared to past performance. When flushing the unit after use with the concentrate valve open, almost 1 gal/minute can go through the unit so no clogged intake. Now with a couple days between sap flows, I'll do some tests at the house before the next run and see what I find.

[RC Maple]

Update

I did have time to set up the unit inside today. I ran straight tap water through it as I boiled the last of the sap I had yesterday. I know there is a difference between running sap and water but I had to re-adjust the settings from yesterday which meant the flow from the concentrate hose was a whole lot higher (i have measured output every day to be sure it is set correctly). I measured the output at one qt in just under 30 seconds. That's 2 qts/min or 30 gal per hour, over twice what I measured in the previous boiling sessions with sap at 2-3%. The tap water is 69 degrees which helps too. Did I have something in the system slowing it down? My rate while flushing the system is 1 gal/min with no restriction in the concentrate line. I am looking forward to seeing what kind of rate I get once the sap starts running again.

[maple flats]

Do a soap wash then an acid wash, a full rinse then check again.
Yes, temperatures have a big effect on flow rates.

[maple flats]

Are you following manufacturer's cleaning instructions often enough?

[wnybassman]

The flow coming out of the concentrate is anemic compared to past performance.

Personally, I like anemic concentrate flow. That means there is more permeate flow. lol

[RC Maple]

Are you following manufacturer's cleaning instructions often enough?

Yes. I have flushed the unit as recommended after every use and at the end of the season. It has always been a wonderful time saver and made syrup season better. It has just seemed to have a bug in the system this year, maybe something I have done wrong without knowing it. I did have to undo some connections two times when swapping out parts which introduced the possibility of error. I have checked and rechecked the connections. I am encouraged by yesterday's test and want to see what it does with the next round of sap.

[BAP]

Yes. I have flushed the unit as recommended after every use and at the end of the season. It has always been a wonderful time saver and made syrup season better. It has just seemed to have a bug in the system this year, maybe something I have done wrong without knowing it. I did have to undo some connections two times when swapping out parts which introduced the possibility of error. I have checked and rechecked the connections. I am encouraged by yesterday's test and want to see what it does with the next round of sap.
You haven’t answered the questions asked by a couple of people as to whether you are doing soap and or acid washes. Rinsing alone will not keep the RO clean and flows up.

[RC Maple]

You haven’t answered the questions asked by a couple of people as to whether you are doing soap and or acid washes. Rinsing alone will not keep the RO clean and flows up.

Sorry, I didn't read the soap and acid washes as a question but a recommendation. I do a soap wash with the recommended preservative at the end of the season. I have never seen a recommended acid wash. My original membranes lasted over 3 seasons and were still performing at concentrating sap, they were just slowing down. I had new ones on hand so I changed them 4 weeks ago.

[Amber Gold]

I recommend doing a soap wash after every use. That way they're always fresh. Unless it's a small run (relative to the size of your system), I don't think just a perm. rinse does a good job getting all the boifilm off the membranes. IMO.

Do you have hard water and do you rinse with well water often? If not, an acid wash may not do much.

[Amber Gold]

I recommend doing a soap wash after every use. That way they're always fresh. Unless it's a small run (relative to the size of your system), I don't think just a perm. rinse does a good job getting all the boifilm off the membranes. IMO.

Do you have hard water and do you rinse with well water often? If not, an acid wash may not do much.

[canaanmaple]

I recommend doing a soap wash after every use. That way they're always fresh. Unless it's a small run (relative to the size of your system), I don't think just a perm. rinse does a good job getting all the boifilm off the membranes. IMO.

Do you have hard water and do you rinse with well water often? If not, an acid wash may not do much.

yes, warm soap wash often is important. Especially mid-late season. I can see the wash kettle water turn amber sometimes! Just have to have enough permeate to flush. I know for my 4x40 membranes its at least 200 gallons to flush after the soap wash.

On a side note, it was balmy mid-season day yesterday in the 50s and my 200gph unit was getting about 222 to start so I got through concentrating in record time :)

[SeanD]

I agree with the more frequent soap washes. You get a lot of bang for your buck with washes. It takes no more extra time at the end of your boil than the hot water rinse and backwash. I've only got 200 gal to process today, but I'm going to do a wash bc even though the sap lines will be shut down for the cold over the next few days, any critters on the membrane will have a party.

All that said, you may have a few issues going on and need multiple approaches. Maybe you already took care of it on your last test. You can get a jump on your live test in the next flow by making your own sweet to run through. The warm plain water went through well, but try mixing some sugar in a 5 gal bucket of colder water. Mix it warm then let it sit outside for a couple hours. Shouldn't take long to get it down to 34 deg or whatever your original conditions were. It shouldn't take much sugar to get the water to 2%.

[RC Maple]

Thanks to all for the good info on maintaining my RO. With more frequent soap washes I may be able to go even longer before new membranes next time and better performance in the meantime.

[eustis22]

Does anyone know why only one outlet port of the membrane housing would pass fluid thru it? Initially I thought I had my ports mixed up but even switching the permeate and concentrate lines doesn't result in the other line getting any output. Yesterday I basically pumped my holding tank into my concentrate tank. Very frustrating as I have a LOT of sap to RO.

[Bricklayer]

If you’re only getting flow from 1 port and it’s a steady flow it’s Probley your concentrate port. On a membrane canister it’s the outside ports that are the sap in/ concentrate out and for permeate it’s only 1 port for permeate out. The other port on the canister has to be plugged.
If you have it hooked up right and you’re getting 0 permeate flow. Then you either have a really bad plugged up membrane , a plumbing issue or your not creating enough pressure with your pumps or restricting the flow enough to create the back pressure needed to force the sap through the membrane.

[eustis22]

plumbing issue?

I tried just using one membrane (in case one was bad) but the effect was the same...just flow from the concentrate port.

I was informed my Coronwater TYP-8900K pump would be strong enough to push thru two MES 400 GPD membranes. I upgraded from four 150 GPD membranes because it was taking too long to push out 100 gallons of sap.

[Bricklayer]

So you’re using new membranes ?

[Bricklayer]

You should start a new thread. Kind of hijacking this one. Post some pictures and a good explanation of your RO , Pump and membranes and I’m sure someone will have the solution.

[maple flats]

You should get more permeate flow if the RO is removing more than 50% of the water in a single pass. If removing less than 50% of the water, you will get less permeate flow. However if no permeate flow, a couple of questions. What pressure are you operating at? How many GPH is your pump moving?
Answer those along with rechecking your connections.

[eustis22]

Apologies for the hijacking....I will indeed start a new thread and put up some pics of my set up