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Anyone use a CO2 degasser tower on their RODI system

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I have been burning through resin and upon talking with spectrapure they said I should check my CO2 levels in the water. Turns out they say under 10ppm is reasonable. I’m at 41ppm based off of their test kit. 

 

He he said I could set up a degassing tower but I’m not sure how that would work. He sent me a link to an R2R thread but without seeing one first hand, it’s a little difficult to determine how it works. 

 

Since a a bunch of other people are on well water, I’m wondering if anyone has one and if I can come check it out. 

 

I am limited on space so that is a concern also. 

 

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No. I built a small one one but never hooked it up. I even have a 30-gallon storage container and a DC RV pump that I was going to use to build an even larger one but... I never got around to that either. This IS what I did do, however, and my experience:

 

First, I tried going without DI resin - for a similar reason that you're probably contemplating: Burning through expensive DI resin. I was going through a whole resin charge after less than 100 gallons of production. But, before taking the resin out, I sent in samples of my tap water (well water) and my RO water to ATI for an ICP-OES test. They allow you to send in two vials - one being your tank water and the other your fresh water and they run them both through the ICP-OES equipment. That's two ICP tests for the price of one more-less. (They don't test the FW vial for alkalinity, though.) My water came back rather clean except it had a small amount of trace metals in it with nickel being among the higher ones. Still, I gave it a shot and took the resin out. That didn't work out for me. After some months, I noticed corals starting to look bad and then entered a time of STN. I lost a lot for a reason I wasn't sure about. Sent more water samples in and found that my nickel levels were unusually high.

 

Then, going back to my ICP test results, I noticed that most every "(really) bad ion" that was in my well water was positively charged. Well, the dissolved CO2 molecule is associates itself with the OH- in water and is, therefore, negatively charged. So what I did was to run just cation resin which grabs positive charges and skipped the anion resin. Basically, I ignore the dissolved CO2 and any other negative ions, letting them pass.  I've been running that for 6-7 months now and things seem to be good again. The resin that I used was from batches of old mixed bed resin that I separated myself. However, I noticed a couple of months ago that BRS started carrying color-changing single-bed anion and single-bed cation resins which make this kind of setup easier for folks. 

 

Now, about degassing towers - Spectrapure has a diagram on their website. You can see it here. It basically just aerates freshwater to "blow off" the excess CO2 - an old airstone skimmer would work but, in the diagram, it's just a PVC column with an airstone bubbler at the bottom. The problem I had with this is that the stage has to precede any DI resin stage and, coming out of this device, it's under no pressure whatsoever save gravity. I wasn't terribly crazy about that idea because, with a little back pressure or clogging, I'd have water coming out of the top of the degassing tower. So I had this idea of using a bigger reservoir for aerated output and tying it in to the DI resin stages through the same kind of pump used to deliver water under pressure in recreational vehicles. 

 

Anyways, I hope this gives you something to think about and hope that you find a solution. The principles are pretty simple, though.

 

 

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This old RC thread describes another approach. In this case, he holds his tap water (from a well) in a 50 gallon container with an airstone. He then uses a booster pump to feed the water from that container to his RO/DI unit. I actually kind of like that approach. It's straightforward and leaves the RO/DI processing chain intact.

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