Depleting DI Resin too quickly

Discussion in 'General Reef Discussion' started by Brad M, Aug 20, 2019.

  1. Brad M

    Brad M Plankton

    I am having issues with my DI resin depleting too quickly (after 30 gallons or less). I am on well water and have a TDS of around 17-20 (it fluctuates). So I bought a 4 stage RODI system from BRS with water saver (2 RO membranes).

    Yesterday I added a booster pump because my pressure was way too low (25), because I thought that was causing the issue. After I added the booster pump I changed all of my filters including my RO membranes,and I flushed the new filters individually as per the directions. Then I changed out the depleted resin, and ran a batch of water overnight.

    When I went to bed it was 4 TDS before the resin and 0 TDS after. I made roughly 30-35 gallons of water and it reads 1 TDS this morning. My system now reads 4 before and 4 after the resin, and it has changed completely to brown after only making about 30 gallons of water.

    Any thoughts as to why I am having this issue? Or suggested fixes?
  2. huntindoc

    huntindoc RRMAS BOD Membership Director Staff Member

    With a TDS of 17-20 (that's phenomenal by the way) it has to be dissolved CO2 doesn't it? You may have to put water in something like a Brute trash can and aerate the heck out of it and use a pump to supply your RO/DI.
    Brad M likes this.
  3. Brad M

    Brad M Plankton

    Is there a way to test the water for dissolved CO2 first? To make sure that is the issue. I would like to avoid spending more money fixing the wrong issue again.
  4. Brad M

    Brad M Plankton

    Another suggestion on Facebook is my water hardness being on a well. The dissolved minerals are making it through the RO and quickly depleting my DI. How would I tell which one is the issue. Because they are both going to be potentially costly to fix.
  5. huntindoc

    huntindoc RRMAS BOD Membership Director Staff Member

    Dissolved minerals should show up on your TDS. If you only have 17-20 TDS coming from your well there is really nothing else it could be other than CO2 (which does not show up on TDS). This problem is fairly common with well water. A small submersible pump and a Brute trash can shouldn't cost very much.

    I don't know of a test kit for CO2 but you could take a sample of your well water and check pH(fresh out of the faucet), aerate the heck out of it and see if the pH rises significantly. If it does you have confirmed there is CO2.
    Brad M likes this.
  6. Brad M

    Brad M Plankton

    The cost problem with CO2 is I don’t have room in my guest bathroom for another brute trash can. Which means getting a plumber to run a water line to my garage and move everything out there. Which I honestly need to do anyway. I will give the ph test a try.

    For a short term “fix” I am upgrading to a 3 stage DI resin using cation, anion, and mixed separately. That way I can replace only the one that runs out first.
  7. Brad M

    Brad M Plankton

    I just wanted to update everyone on my new split bed resin approach. I ended up buying a triple DI saver thing from BRS. I am now running my setup as follows.

    Sediment filter -> carbon filter -> 2 RO membranes -> cation DI resin -> anion DI resin -> pro mixed bed DI resin -> Normal mixed bed DI resin (not needed but I had the resin and spare canister so I went for it)

    Last night I made my normal 30-35 gallons of RODI water, and it depleted less than half of the anion stage. The other stages still look full. So I think that does point towards CO2 being the issue and not the hardness of my water. Since cation resin does minerals like iron, and anion helps with CO2. But more importantly this looks like a successful bandaid until I can hire a plumber to run water lines into my garage. Where I have room to setup a proper fix for the CO2 issue.
    Adam Mulling likes this.
  8. graciesdad

    graciesdad Treasurer Staff Member

    Glad you have a solution.

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