RO membrane replacement

[Ray J]

Can someone recomend a good membrane replacement for a Kent Max. four stage system...75 or 100 gal per day. also how long do they last with a 10% water change monthly on a 110 gal, tank.

Ray

 

[afishyonados]

I would choose a low output unit such as Kent's 24gpd Hi-s. If you can keep the unit almost continuosly running, it will prevent the carbon cartridges from becoming biological while unused. If the unit spends alot of time off, the nitrogen based compounds sitting still in the cannisters will encourage bacteria to grow. The problem with that is when coated with an active bacterial slime, the carbons effectiveness is diminished, possibly resulting in chlorine getting to the membrane, which would kill it.

 

[ERTLEY]

I would change your membrane anually,also i would change 25% of your water monthly,or less weekly!!10% is not enough to me.The kent replace membrane is what i used.And works very well.Hope this helps!

 

[Ray J]

Has anyone tried the "Desal" or " FilmTec " membrane ? if so your opinion, also a correction my water change is aprox. 20% a month not 10%.

Ray

 

[smleee]

You want a genuine DOW FilmTec membrane (I would assume it fits in your unit, but don't quote me on that). Also there are some cheap imitations of these that only use the FilmTec material.

eee

 

[ohioreef]

<a href=showthread.php?s=&postid=6996146#post6996146 target=_blank>Originally posted</a> by ERTLEY
I would change your membrane anually

My understanding has always been that the membrane doesn't need changed that often. I've heard of people having membranes that are 3-4 years old or older.

I've always read that there's no need to change it until the output TDS readings begin to creep up.

 

[northbay-reefer]

I agree with ohioreefer, the membrane doesn't need to be change that often. The carbon, sediment and DI cartidges are the ones needing to be replace on a regular basis

 

[smleee]

Unfortunately you cannot go on a time basis on when to replace the membrane. Everyones TDS and production amounts will differ vastly. You would need to calculate the rejection rate of the RO ouput only and see if you are getting somewhere above a 90% rejection rate (as with the DOW FilmTec, this is probably when you would want to replace it).

eee

 

[ERTLEY]

According to my testing of my own system,Micron every 3-4 months,carbon block-n-gac filter 6 months,d/o and membrane anually.I just got in the habit of doing this,so there is no probs with my r.o. water.Never had any in 5 years

 

[Ray J]

Is there a meter to measure the "TDS" I dont remember seeing anything like that at the local LFS

 

[ERTLEY]

Yes there are tds meters.There about $60.00.Then you'll know if your water is up to par.

 

[smleee]

This is the one that came with my RO/DI unit.

http://www.airwaterice.com/product/TDS4TM

eee