RO issues... need advice

flyhigh123

funky member
I've been having issues with my tap water and RO system for a while now....

my tap water has a 350+ TDI, and i would say the water is on the hard side. With RO membrane, it gets to 30-50.

I have a 75gallon RODI system. The water pressure is around 75 psi.

Currently i seem to be blowing through my RO membrane every 3-5 months... and i'm getting tired of replacing it. The Membrane i use is DOW brand. I end up blowing through DI really quick as soon as the RO membrane starts to increase in TDI.

I normally run the RO unit 3 hours a day which is hooked up to a water timer.

Can anyone suggest to me what I can do?

If I go down to a 25 gallon or 50 gallon a day RO membrane, does that help?
 

Justdrew

Dad with Triplets!
Something out of the ordinary is going on. I have a Dow 75 gpd that is over 6 years old. I still get 97% rejection from it. This is with tap water in the 600-700 yes range. I change my prefilters regularly and have never had an issue. What quality prefilters are you using? That is the only thing that would lead to premature membrane fouling.
 

shifty51008

12-5 Chiefs record
I have around 350 tds out of my tap with very hard water and after the membrane it brings my tds down to 4 or 5 and this is a 3 year old membrane.

Are you sure the membrane is pushed all the way in the housing? It can be a tight fit.

What is your good to bad water ratio? Should be about 1:4
 

flyhigh123

funky member
hmmm...

i've changed out the ro membrane plastic outside chamber as well thinking it could be a seal issue.

Do you guys know what your water pressure is? I can control the pressure and was thinking if that could be the cause.
 

flyhigh123

funky member
Something out of the ordinary is going on. I have a Dow 75 gpd that is over 6 years old. I still get 97% rejection from it. This is with tap water in the 600-700 yes range. I change my prefilters regularly and have never had an issue. What quality prefilters are you using? That is the only thing that would lead to premature membrane fouling.

it could be the prefilters too... i did swap them out once already...
 

azjohnny

New member
You have something wrong with your filter, with TDS levels @ 350 the TDS coming out of the membrane should be in the low single digits.

I have 650 TDS and my TDS level coming out of the membrane is 8. I run my Maxcap at 100 PSI

What is the micron size of your sediment and carbon filters?
 

andy01748

New member
Chlorine or chloramines in municipal water can damage your membrane if the carbon block is used up and can't absorb anymore prior to your membrane.
 

dunk373

New member
i always run a whole house carbon to make sure any chlorine wont make it to the membrane i have a 12 year old membrane still good. As stated earlier make sure you have a carbon pre filter if you dont one can easily be added for a low price
 

flyhigh123

funky member
ok, just ordered a refilleable carbon chamber... will be putting that in and new 1 micron filters... will report back and let you guys know...

how do i know when the carbon is used up?
 

shifty51008

12-5 Chiefs record
The only way to know for sure is to test for chlorine after the carbon stage. But you should be fine as long as you replace it regulary
 
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