Problem with RODI unit.

ValorG · Dec 24, 2015

So I'm having problems with my rodi unit not really working well at all. It's been ongoing and have went through 2 membranes already. My tap tds is about 130-150 and my rodi would make it go down to about 70 and this would eat up my di beads real quick. I read up that a may need a pump booster so I got one and decided to just start and get all new filters and new DI resin.

I'm making water and its coming out 0 tds and im like great problem fixed. Then I notice my di resin starting to change colors already... ughhhhh. So I test the water coming out of the membrane and its 110. keep in mind my tap is 130-150 and this is with a booster pump. Should I just chuck this thing and get an all new unit? It's really frustrating.

AZDesertRat · Dec 24, 2015

Post some photos of the plumbing. You may have it plumbed wrong or it is possible your membrane housing is cracked and water is bypassing the RO membrane.
What is your exact measured waste ratio? What are you running for pressure on the booster? What is your water temperature and have you run hot or warmer water through the membrane which would damage it? What membrane do you have and what are you using for sediment and carbon block filters?

BetURWrasse · Dec 24, 2015

Maybe you need a 6 stage

jbm421 · Dec 24, 2015

I would check to see what the chloramine levels are that will eat up a membrane really quick and if you have high levels of that it could be getting passed the pre filters and breaking down your membrane.... Seems to be happening a little fast for that though

AZDesertRat · Dec 25, 2015

The word stages really doesn't mean much and more stages is not better. Fewer, more efficient stages is always a better idea. Most users are served fine with 4 stages. With a tap TDS of only 130-150 the OP easily fits in this category.

AZDesertRat · Dec 25, 2015

As long as you have a 1 micron or smaller sediment and carbon block filter and the carbon is not exhausted, chloramines would not be an issue. The chlorine portion would be absorbed by the carbon block and the ammonia that is left over after the RO membrane is removed by the DI. Carbon does not remove chloramines as many try to make you believe.

jbm421 · Dec 26, 2015

AZDesertRat said:
As long as you have a 1 micron or smaller sediment and carbon block filter and the carbon is not exhausted, chloramines would not be an issue. The chlorine portion would be absorbed by the carbon block and the ammonia that is left over after the RO membrane is removed by the DI. Carbon does not remove chloramines as many try to make you believe.

So are you saying that chlorine will not ruin a membrane?

AZDesertRat · Dec 26, 2015

No, chlorine will destroy a TFC RO membrane. The 1 micron carbon block will adsorb the chlorine for 12,000 gallons of water if you protect it with an equal sized or smaller sediment filter. A 0.5 or 0.6 micon carbon block will adsorb 20,000 gallons worth.

jbm421 · Dec 26, 2015

AZDesertRat said:
No, chlorine will destroy a TFC RO membrane. The 1 micron carbon block will adsorb the chlorine for 12,000 gallons of water if you protect it with an equal sized or smaller sediment filter. A 0.5 or 0.6 micon carbon block will adsorb 20,000 gallons worth.

Thanks for the info... they don't give enough information about these things when your trying to buy them. I think Spectrapure's site is one of the few that give out some good info when your shopping around for them.

james983 · Dec 26, 2015

AZ is an expert in this area and I would follow his suggestions and would like to add one more. AZ is it possible that his RO is not seated properly?

jbm421 · Dec 26, 2015

james983 said:
AZ is an expert in this area and I would follow his suggestions and would like to add one more. AZ is it possible that his RO is not seated properly?

I was thinking that as well. Don't they pop or something when you get them into place? This happen to me once had a membrane housing that was just a pain on a coralife unit.