DIY RO operation help

[Lucky Dog]

Hello, I've got a DIY RO setup that I put together and I am starting to wonder if I am running it correctly.

I have the aquatec 8800 pump, filter and 4 100gpd membranes.

It takes about 8 hours to get 5 gallons of concentrate to 6-7%. Generally from about 20 ish gallons of sap.

The way I run it is to restrict the concentrate line to build pressure (approx. 80 psi) and leave the pure water hose wide open.

Is this correct? It seams very slow.

[jrgagne99]

I think you're running it right, but increase the pressure to 110-120 psi. Permeate flow rate will increase significantly.

[Lucky Dog]

I think you're running it right, but increase the pressure to 110-120 psi. Permeate flow rate will increase significantly.

I can only seem to get it up to 80 psi with the current pump.

[EriobNY]

Sounds good. I just run until I take out 50% permeate . Not sure of pressure but restrict until I get about equal flow on both lines.

[DRoseum]

Which specific 8800 model number? There are various ones with different performance curves (pressures and flow rates).

Also, the 100 gpd membranes are most likely contributing to the slowness a fair amount. That rating is a flow rate rating. It literally takes 24 hours to process 100 gallons of raw water (producing 50 gal of permeate and 50 of concentrate). Now, at lower pressure and lower fluid temp that performance can go down significantly. 50 - 75% of that rating. 60% is safe bet.

Also, if those are in series, the flowrate to the last one is going to be tiny and decrease performance even more.

[Lucky Dog]

Thanks for the replies. It sounds like I may not be as bad off as I thought.

What changes should I make to increase my through put for next year, I just can't keep up any more.

[clifford5555]

Just curious, do you have your sap source higher than your pump? I lifted my bucket of sap from the ground up onto a chair and I was doing 5 gallons in about 90 mins and it was ready to boil.... That extra gravity makes a HUGE difference.

http://mapletrader.com/community/showthread.php?35288-RO-Homemade-System-Problem

[Lucky Dog]

Just curious, do you have your sap source higher than your pump? I lifted my bucket of sap from the ground up onto a chair and I was doing 5 gallons in about 90 mins and it was ready to boil.... That extra gravity makes a HUGE difference.

http://mapletrader.com/community/showthread.php?35288-RO-Homemade-System-Problem

No, I don't. I may try that, but then it is harder for me to get the sap into the container.
I have a different pump on order that I want to try, it is a self priming pump that is supposed to get up to 160 PSI.

[clifford5555]

From Aquatec: https://www.amazon.com/gp/product/B00ENPZE5Y/ref=ppx_yo_dt_b_asin_title_o03_s01?ie=UTF8&psc=1

"Pressure switch is not included in this listing. Pressure switch need to be purchase separately. Depending on your applications at what cut-off pressure setting. This listing is for pump and transformer only. You can turn on/off manually, or use (optional) pressure switch or (optional) timer to turn on/off the pump. This pump is to increase input pressure to a RO system. This pump is not for increasing pressure to ice maker or refrigerator. That's different model. For ice maker pump or increasing output pump, please get Aquatec 5851 0.7GPM to 1 GPM pump This is Aquatec Boost pump and transformer for Reverse Osmosis Water systems. The input/output of the pump is 3/8" quick connect fitting, we also include two reducer fitting to 1/4" if you have 1/4" tubing. So this setup will work for both 3/8" and 1/4" OD tubing. If you are using this for a RO system you may need to order separately a pressure switch and/or a solenoid valve. If you are buying this pump for misting application. Please note that the pump need to be placed at floor level, the pump need to be lower than the water level. It can self prime but input tubing need to be all the way near the bottom of the container and be tied down/ tether with heavy object so the tubing can stay near the bottom and not floating up. The number of nozzles the pump can support depends on the flow rate of the total nozzles and the pressure you want to achieve. Connect one nozzle first and make sure everything works then add more nozzles and check pressure. With less nozzles the pump is able to high pressure above 80 psi. As you add more nozzles, the pressure decreases. If the pump is not connecting to anything, or just pumping air, then it sounds loud, it will be more quiet when it is connected with water line. The pump need to be placed on the floor level, lower than the water level. Do NOT put the pump on top of the container or above water level if you are drawing water from a container.

READ THAT LAST LINE IN BOLD! this is what I read that solved my problem. I thought, no way it could be that easy....but it was! Good Luck to ya!

[jimmol]

Being below the level of the fluid will help. This pump has a 60" draw, so in theory you could place it 5 feet above you liquid and it will suck it up to the pump. Once the pump is primed, it will continue to draw until you run out in sap bin. I use a 30gal food grade trash can to collect my sap and if I put up, I would still have to draw the sap the height of the can (40"?) before it would flow down to the pump. If I had a spigot at the bottom of my collector, then it sure would help to raise it.

There is a set screw on the pump end that will allow some adjustment. Read the instructions. I have mine about 3/4 the way down. This may give you the added boost to your pressure.

My home made RO uses a 3/8 line for input and 1/4 for the rest of the tubing. After it is primed, my needle valve is set to barely opened to give me 120 psi on my 150GPD membranes. Since I am running 18 taps, one day I will collect and begin the RO process. Then, when the can is empty, I take the input and put it in the concentrate and let it run over night to increase the concentration. By then, the collector can may be ready so the process starts again after removing the concentrate for boiling. Of course when the temp drops below freezing, I bring the rig inside to rinse it for a couple of hours with warmed pure water collected from the ro unit earlier.

[DRoseum]

I have a different pump on order that I want to try, it is a self priming pump that is supposed to get up to 160 PSI.

Curious, what pump is that? Make and model? Link to check it out?

[EriobNY]

Restrict output so that permeate and concentrate lines flow the same.


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[Lucky Dog]

There is a set screw on the pump end that will allow some adjustment. Read the instructions. I have mine about 3/4 the way down. This may give you the added boost to your pressure.



Interesting, I'll have to see if mine has adjustment. It never occurred to me to read directions. :)

[Lucky Dog]

Restrict output so that permeate and concentrate lines flow the same.


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I've got my concentrate like restricted to a fast drip, that is the only way I can get to 80 psi. If I open the flow up any more, I can only get to 4% or so.

[Lanark]

I need help with my home made reverse osmosis, the port on the lower left of the first housing does not push water to the top of the second housing, nor does the left port on the second housing push water to the top of the third housing. Whether the needle valve is open or close the dial on the pressure gauge does not change. The motor is a residential grade reverse osmosis booster pump 200-300 gpd.212722127321274

[carls47807]

Your lower ports in the membranes are reversed. Center is water the one in the right is concentrate.


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[carls47807]

Luck dog,

There is a 2mm Allen screw in your pump head. You can turn it in to increase the pressure.


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[Lanark]

Thank you, my other question then if it's reversed is, on my third housing the left port is 1/4" tubing where all other tubing is 3/8's. Does this make a difference or should all tubing be 3/8's?

[carls47807]

Plumb the three center water ports in 3/8. Plumb the first two concentrate ports in 3/8 and terminate it to 1/4” with a needle valve.


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[Lanark]

I just checked the schematic of the RB20 on the RO bucket site and the concentrate line is on the left of the third housing with the needle valve, so I'm unsure how mine is reversed.

[carls47807]

The RO Bucket doesn't use an off the shelf residential membrane housing, they are specially made for their application. Your housing has the water port in the center and the concentrate line off to the right (the fitting that is slightly higher is always the concentrate port). Different manufacturers put their concentrate port on different sides.

If you just switch all your bottom ports (keep all the hoses connected as they are) it will be plumbed correctly.

Also it looks like you are using vinyl hose? That might pop out of the push connects when you build up pressure. You should use HDPE or LLDPE hose for the pressure side (permeate will work with vinyl).

[Lanark]

Thank you for your help.

[Lanark]

Since having some technical problems with my home made RO the only thing ran through it was distilled water. That being the case, do I still need to run a preservative through the filters for storage or will they be fine with the distilled water?