Water source question

childress5tyler · 01/20/2017, 08:11 AM

Hello,

I have two water systems in my house, one that is hooked up to a water softener and on that is not. Currently, my RODI system is hooked up to a shower in the back of the house that is not filtered by a water softener. I am considering moving my RODI system to the part of the house that is hooked up to the water softener because after using the system for a while I'm having a brown/copper like substance grow on the sides of the canisters. I've never tested to see if this is copper (I'm on well water and there is a fair amount of copper in the water, but I always assumed the RODI unit filtered it out), but have never had any issues. Should I move my RODI unit to the part of the house that is hooked up to the water softener so it can have an initial filter before hitting the RODI unit? To sum up my question, would you hook your RODI unit up to the non-water softener part of the house or the water softener part of the house?

nereefpat · 01/20/2017, 10:59 AM

Water softeners aren't really filters. They just exchange softener salt for the calcium and magnesium carbonates that are present in the source water.

I have really hard water, and I've never noticed any scaling from the hard water causing early failure of my RO membrane. I don't think it will matter whether you use hard or soft water for the RO feed.

As far as the copper, the carbon blocks in an RO system will remove the copper from the feed water.

timnem70 · 01/20/2017, 01:39 PM

What he said

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bertoni · 01/20/2017, 05:36 PM

The softener might help the RO membrane last longer by reducing precipitation on it, so I'd use the pre-softened water. I agree, though, that it might not help much. That'd depend on a lot of things, including the rejection rate of the membrane itself.

outssider · 01/20/2017, 06:38 PM

I'd bet that the accumulation of dust/material on the inner side of the canisters is not copper. i'd first suspect rust from iron in the well but if it were copper i'd be concerned.

bertoni · 01/20/2017, 08:06 PM

I agree that the reddish brown is rust. Copper would tend to be green, I think.

childress5tyler · 01/21/2017, 09:47 PM

Quote:

Originally Posted by outssider

I'd bet that the accumulation of dust/material on the inner side of the canisters is not copper. i'd first suspect rust from iron in the well but if it were copper i'd be concerned.

Is rust from the iron something that I should be concerned with? Would the carbon block filter the excess iron out?

Also, this is the water that I've used in my sps reef before and never had any issues - also makes me think that is rust. Copper would destroy a reef.

bertoni · 01/21/2017, 09:52 PM

Excess rust might plug the RO membrane over time, but that's unclear. A good sediment and carbon block will help keep larger particles away from the membrane, which seems to be good enough.

01/20/2017, 08:11 AM	#1
childress5tyler Registered Member Join Date: Sep 2012 Location: Indiana Posts: 52	Water source question Hello, I have two water systems in my house, one that is hooked up to a water softener and on that is not. Currently, my RODI system is hooked up to a shower in the back of the house that is not filtered by a water softener. I am considering moving my RODI system to the part of the house that is hooked up to the water softener because after using the system for a while I'm having a brown/copper like substance grow on the sides of the canisters. I've never tested to see if this is copper (I'm on well water and there is a fair amount of copper in the water, but I always assumed the RODI unit filtered it out), but have never had any issues. Should I move my RODI unit to the part of the house that is hooked up to the water softener so it can have an initial filter before hitting the RODI unit? To sum up my question, would you hook your RODI unit up to the non-water softener part of the house or the water softener part of the house?

01/20/2017, 10:59 AM	#2
nereefpat Registered Member Join Date: Apr 2016 Location: Central Nebraska Posts: 3,190	Water softeners aren't really filters. They just exchange softener salt for the calcium and magnesium carbonates that are present in the source water. I have really hard water, and I've never noticed any scaling from the hard water causing early failure of my RO membrane. I don't think it will matter whether you use hard or soft water for the RO feed. As far as the copper, the carbon blocks in an RO system will remove the copper from the feed water. __________________ Pat Current Tank Info: 125 in-wall , 40b sump. 6 bulb T5. ASM G2 skimmer. LPS and leathers

01/20/2017, 05:36 PM	#4
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	The softener might help the RO membrane last longer by reducing precipitation on it, so I'd use the pre-softened water. I agree, though, that it might not help much. That'd depend on a lot of things, including the rejection rate of the membrane itself. __________________ Jonathan Bertoni

01/20/2017, 08:06 PM	#6
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	I agree that the reddish brown is rust. Copper would tend to be green, I think. __________________ Jonathan Bertoni

01/21/2017, 09:52 PM	#8
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Excess rust might plug the RO membrane over time, but that's unclear. A good sediment and carbon block will help keep larger particles away from the membrane, which seems to be good enough. __________________ Jonathan Bertoni

01/20/2017, 01:39 PM	#3
timnem70 Registered Member Join Date: Apr 2015 Posts: 462	What he said Sent from my SM-G930V using Tapatalk

01/20/2017, 06:38 PM	#5
outssider Registered Member Join Date: Nov 2009 Location: Reseda, Ca. Posts: 1,717	I'd bet that the accumulation of dust/material on the inner side of the canisters is not copper. i'd first suspect rust from iron in the well but if it were copper i'd be concerned.