Low RO DI water production

[skripo]

About 6 years ago I built my own DIY 4 stage 150 GPD RO DI system which worked well enough. I never really used that much as I only had a 12 Gal JBJ at the time. I had installed my 180 GAL but never got it going because we sold the house. I tore it down but left the membranes in the housing when we moved.

I recently decided to jump back in so I set up the system. The membranes had hardly any use but were stored wet. There was no smell when I opened the canisters and they looked fine, as far I could tell anyway. All other media is new.

I'm pretty sure I hooked it up right but get very little production with lots of air in the output line. Are my membranes shot? Didi I plumb it wrong?

1) Water to particle filter in
2) Particle filter out to carbon in
3) Carbon teed to pressure gauge and auto shutoff in
4) Auto shutoff out to membrane in
5) RO water out to check valve
6) Check valve auto shutoff in
7) Auto shutoff to DI in
8) Membrane waste out to combination 800 restrictor / flush valve

Pressure when flushing is 40 PSI, 58 PSI when restricted.

 

[skripo]

Forgot to mention that in step 3 it goes to high pressure side of auto shutoff and 6 goes to low pressure side of auto shutoff

 

[AZDesertRat]

Take a look at this diagram:
http://spectrapure.com/huds/DUAL.pdf

One thing I will point out is membrane manufacturers recommend a minimum of 65 psi incoming pressure with dual membrane systems. You will also have reduced production in winter months when the water temperature is colder and more dense. As far as the air, try running the system and pick it up in your hands and rotate it around in different orientations to release trapped air inside the housings.

 

[skripo]

Actually I only ran it with a single membrane at first and still had the same problem, I added the second after.

I will pick up a new one, I want water now.

 

[cdness]

If the membrane is 6 years old, I would recommend changing it out just due to age...

However in addition to that, the 150 GPD systems need higher pressure to run right. You may be better off with a 90 GPD TESTED membrane from Spectrapure to still give you the higher output while not requiring as high of pressure...

Can you measure the amount of water in the waste side to make 100 ml of good RODI water? This will give you the waste ratio of the membrane.

 

[skripo]

Thats exactly what I plan to get. I am leaving right now to get it.

 

[AZDesertRat]

I wouldn't abandon your existing membrane just yet, it may still be good if it remained wetted.

What is your water temperature? Also measure your exact waste ratio using a measuring cup and clock or watch. First measure the waste flow for exactly one minute and record the amount in m/L or Oz then do the same with the treated flow. It should be between 3:1 and 4:1 waste to good. In winter months with colder water this can go up drastically and if you are using a flow restrictor set for two membranes you are probably sending way too much to waste robbing you of pressure even further.

You may have a hard time finding Spectrapure products in Canada but thye are worth the effort.

 

[skripo]

I am not a fan of Spectrapure or any other filter system. They are all off the shelf parts, except for their 90 GPD membrane. That being said, they are competitive and I would buy them if I had to do over. Spectrapure is readily available in Canada and I just got the 90 GPD (regular, not premium) for the $45.00 CDN at my LFS. Thats $38.25 USD.

The membranes are toast, system started working perfect with the new spectra pure membrane.

Thanks for the help people!

 

[AZDesertRat]

Glad its working. Make sure to check and adjust the waste ratio to keep it in optimal condition. Being in the treatment industry I would have to disagree with you on "all off the shelf parts". No other vendor long term tests every filter and component before offering them for sale or even has components and filters manufactured specifically for them. Also no other vendor cuctom blends all their own DI resins based on thousands of hours or real world testing. Reef and aquaria is just a small part of their business, they are big in the hydrogen fuel industry where ultrapure waters are critical and also big in the coffee industry where RO/DI then remineralization of the water can drastically change the way a cup of coffe tastes. They pride themselves on being innovators not imitators so do not settle for anything off the shelf.