Will this work for RODI?

Discussion in 'DIY' started by Klems, Sep 20, 2017.

  1. Klems

    Klems Supporting Member

    I am not in a position to where I can add an RODI system to our house....but don't want to have to go to the LFS to get RODI.....so I was wondering if this might work

    I can get drinking water from our local "pure water" store. We use it for our main drinking water. I have a TDS meter and it registers "0" tds. If I were to get that water and then pump it thru a stand alone DI resin....would that be the same as an RODI system most of you have in your homes? My assumption is that there would be little to no rejection because it is already at zero TDS....and if it did go higher the DI resin would knock it down to zero effectively.

    All I would need is the DI membrane, two buckets a pump to push the water from one bucket thru the DI membrane and into the other bucket. If this would work, what type / size of pump would I need to get to push the water up to 40-60 psi?
  2. sfsuphysics

    sfsuphysics Supporting Member

    You could push external water through DI resin sure, as long as you do so slowly enough. At the resin part it's not a matter of pressure but contact time, so just make sure it's going as slow as it goes through the membrane, which is about 4gph.

    Also not sure what is preventing you from adding an RODI system, but you can get a fitting that lets you screw onto a standard hose bib (outside) or onto your sink faucet. No drilling or tapping of pipes needed. Now if the issue isn't landlord related but significant other related, then I got no help for you :)
  3. Klems

    Klems Supporting Member

    It's more an issue of not having so much waste water....our tap shows up at over 300 tds.... If I could get water at .20¢ and get a small pump and $40 for di system...that would be great
  4. rygh

    rygh Supporting Member

    Check for chlorine and/or chloramines in that drinking water.
    Likely to have it.

    That will eat up your DI quick. If so, you may want a big carbon cartridge first.
  5. What is the purpose of the DI part of the RODI?
  6. sfsuphysics

    sfsuphysics Supporting Member

    deionizing (DI) resin will absorb everything that doesn't get absorbed by your prefilters and membranes. Think of it as a last bit of "polishing" to make your water as clean as possible.
  7. Flagg37

    Flagg37 Colorado member

    If you're getting 0 TDS from the local water store then there shouldn't be any need to put it through any more filtration.
  8. rygh

    rygh Supporting Member

    An old quote:
    “Stop using TDS as the measurement of water quality. Disinfection Byproducts like Trihalomethanes, Volatile Organic Compounds, METHYL tertiary-butyl ether, chlorine, chloramines, cysts and lead are the primary contaminants to Public Water Systems. They have no impact on the conductivity of the water. Yet these do not register on a TDS meter. And public water systems primarily supply from surface water that tends to have low TDS levels.” ( Water Conditioning & Purification Magazine, March 2009, page 42 )

    So it is correct that 0 TDS likely does not need further "filtration".
    But you need to neutralize the chlorine, and perhaps eliminate copper and lead.

    You can add chemicals to do that, or use carbon, or use DI. Or all 3.
  9. xcaret

    xcaret Supporting Member

    Jim @gimmito has a zero waste water system Kati/Ani for his nano tank
    If waste water is your concern, check that particular system.
  10. Flagg37

    Flagg37 Colorado member

    It would be good to test for those things first then. If they're not present then it saves you the hassle.
  11. Coral reefer

    Coral reefer President

    I'm confused what you're worried about. Just get a multi membrane rodi and make your own.

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