RODI running super slow... help!

[anthonymckay]

Need some help regarding an RODI system. In preparation for filtering 200+ gallons for my new waterbox 230.6, I recently upgraded my RODI with 2 150gpd RO filters running in parallel, to essentially double it to 300gpd. The first day after I set this up I filtered 5gal of water in about 45minutes. It's been 2 weeks since then, and I've filtered maybe 8-10 5gal containers worth of water for ATO and water changes in my current setup. Today I went to filter some water, and it's taken an hour to fill half my 5gal container. My water pressure gauge on the input line is showing 60psi which is normal for it. I'm confused how this has slowed down so drastically in such a short period of time?? Does anyone have an idea as to what might be going on here?

 

[August]

I would change out your sediment filter, which should be your first filter in your setup, and the cheapest filter to change. 60 PSI seems kinda low for a singular 150 setup. Are you running two membranes like a water saver module, cause I have not heard of running them in parrellel without a booster pump. Have you flushed your membrane since you started making water?

edited: cause I couldn't read correctly

 

[Joe31415]

Slowed down drastically...to what? It used to take 45 minutes to fill a 5 gallon bucket, how long does that take now? An hour? 2 hours? A day?

Are you using a booster?

Are these RODI setups new, or do they maybe need their filters replaced/membrane flushed?

Is there more water coming out of the waste line? That is, is it processing the same amount of water, but with more be treated as waste?

Are they both running slow?
*And, if they are both running slow, have you tried just connecting one to see if it's a supply issue?
*And, also, if they're both running slow, were they both previously running correctly?

Is there a splitter that's not fully open or some other blockage in one of the lines?

 

[coralnutz]

Also water temp affects the efficiency as well. Is your flush valve working correctly?

 

[anthonymckay]

I would change out your sediment filter, which should be your first filter in your setup, and the cheapest filter to change. 60 PSI seems kinda low for a singular 150 setup. Are you running two membranes like a water saver module, cause I have not heard of running them in parrellel without a booster pump. Have you flushed your membrane since you started making water?

edited: cause I couldn't read correctly

I'm running them in parallel, so maybe I need to try a booster pump. I thought 60PSI would be adequate but perhaps not? What should my target pressure be?

 

[anthonymckay]

Slowed down drastically...to what? It used to take 45 minutes to fill a 5 gallon bucket, how long does that take now? An hour? 2 hours? A day?

I already mentioned this if you read the original post closer I said it slowed down from 45mins to fill a 5gal container, to 1hr to fill the same container halfway (ie: 45mins -> 2hrs).

Are you using a booster?

Are these RODI setups new, or do they maybe need their filters replaced/membrane flushed?

Is there more water coming out of the waste line? That is, is it processing the same amount of water, but with more be treated as waste?

Are they both running slow?
*And, if they are both running slow, have you tried just connecting one to see if it's a supply issue?
*And, also, if they're both running slow, were they both previously running correctly?

Is there a splitter that's not fully open or some other blockage in one of the lines?

The filters on this Rodi system are all new and were flushed after they were installed. Yes, everything was previously running correctly when it was pushing 5gal in 45mins. Everything is still running correctly, just....much slower.

 

[August]

Your setup intrigues me according to this site, you should be fine, but they do recommend a booster pump in their write up. you will probably have to change out your pre-RO-membrance filters more often. The other thing is that your DI resin containers have a little filter in them that can also get plugged. I have noticed a bump in production when I have changed out the Resin filters which I refilled myself so which are basically recycled.

https://www.aquariumwaterfilters.com/RODI-System-too-slow-Here-is-how-to-make-more-water_b_37.html


I'll be honest though, because I use an auto top off to control water production, I don't tend to monitor how production on my system has changed overall since the install.

 

[KStatefan]

Where is the gauge reading 60 psi?

 

[anthonymckay]

Where is the gauge reading 60 psi?

On the input line right before it enters the first stage sediment filter

 

[KStatefan]

On the input line right before it enters the first stage sediment filter

Would be more useful to have the pressure going into the membrane when making water.

 

[anthonymckay]

Got a booster pump today and bumped the incoming water pressure up to ~100psi. It was oddly still just dribbling out of the RO output line…

Did some more research and found (one of) the bottleneck(s). This system has a “permeate pump” that was rated for 10-50gpd. I removed this, and water started flying out of the RO and Waste lines. The other upgrade I need is a bigger flow restrictor.