RODI question

Discussion in 'Equipment' started by xcaret, Jan 23, 2017.

  1. xcaret

    xcaret Guest

    So I have a couple units, one 5-stage with DI and a 4-stage; both need filters and I'm guessing membranes too. Could I gang those together to make one 7, 8, 9 stage double membrane?
    I have to weigh the price of cartridges vs a new unit; spotted a Vertex with booster pump for what looks a really good price.
    I had a Vertex but when I left the hobby I sold it, now is a regret.
  2. sfsuphysics

    sfsuphysics Supporting Member

    Two issues that come up, both are pressure related.
    Too many prefilters and your pressure is going to drop. And in order to go through two membranes you're going to need/want some good pressure (I want to say at least 60 PSI).

    That said, I run two membranes, the waste output of the first membrane goes into the second membrane, so you basically halve your waste water usage, but I do run a booster pump on it.

    Probably the most you'd want is 4 prefilters, perhaps 2 sediment 5 micron & 1 micron, then 2 carbon blocks going into 2 membranes, but then after that the DI doesn't matter as having more than one stage to go through basically just protecting your laziness of changing, as the first stage will exhaust first and by the time you notice it you can swap the 2nd into the 1st and then replace the used up stuff.
    xcaret likes this.
  3. xcaret

    xcaret Guest

    Yea, I was looking into a booster pump; that was the reason I bought the Vertex in the first place but back then the landlord said no to some minor work to install it at home so it never happened there, then the econnomy crash, out of work, out of hobby... I was sorting more equipment and came across X number of RO units so I had the idea of putting together a nice "drinking water" unit and just hunt for a pump, then I was thinking on pricing all filters and membranes vs a new unit @ $250
  4. Coral reefer

    Coral reefer President

    For drinking water just run the pre filters. Sediment and carbon block. There are lots of other similar to carbon block that do more like lead etc...3-4 stage is plenty to get real nice drinking water imo. No need for a pressure pump that way and no waste either.
    xcaret likes this.
  5. Flagg37

    Flagg37 Officer at large

    Right, most people are fine with drinking tap through a brita.
  6. Coral reefer

    Coral reefer President

    Brita is so so...I think this is way better
  7. WrightReef

    WrightReef Guest

    I used to run a RO/DI Lab and managed a 150GPM (gallon per min) RO/DI system for semiconductors
    Your not going to gain much in these small systems, and would not be effective linking out put to another systems.
    Best use of your 2nd system would be just adding another set of anion/cation resin to the end of the line of system one.
    Then take the Filter, carbon, RO section and making a house drinking water system with it.

    RO is good for drinking
    DI water is NOT but makes a great coffee
    DI water and osmosis - will enter cells and cause them to lysis (burst), also will pull salts and minerals from body as DI water has an affinity to be "dirty".

    I use my RO waste water in the gardens, send down a 100' (large yard) 1/4 tube to a 20' 1/4" soaker line.
    Move around to new spot each time I make water, also good for a summer slow deep soak for a tree.
    xcaret likes this.
  8. xcaret

    xcaret Guest

    Brita... is kind'o like wanting a Ferrari but putting a Ferrari sticker on the hood of my Civic.
    Coral reefer likes this.
  9. xcaret

    xcaret Guest

    I recall reading on no-no to drinking straight DI water. I could then install a divert valve before it hits the DI canister and if I want a really good cup of coffee then flip the valve; perhaps is too much trouble for just drinking water...
    WrightReef likes this.
  10. roostertech

    roostertech reef noob

    I'm splitting mine off at RO stage and add on taste filter for drinking water as well.
    Coral reefer likes this.
  11. rygh

    rygh Supporting Member

    Those "dangers" seem to be 99% hype. Yes, it is "hungry" and will dissolve a few electrolytes and minerals from your spit.
    But that is trivial, and once done, it is the same as tap water.
    Look for scientific studies - can't find any.
    I think a more common issue is that it is not allowed to mix with air first, so PH is way off, and tastes funny.

    But two rare-but-real dangers:
    1) Some of the DI particles can get into the water. They are harmful.
    2) You stripped out the chlorine and chloramine. So harmful bacteria can grow in pipes and tanks.

    Personally, drinking RODI seems like a waste. Prefer a simple carbon filter on the fridge myself.
  12. tygunn

    tygunn Webmaster

    Out of curiosity is anyone using a booster pump with two membranes? After adding my second membrane my booster pump hardly runs unless the pressure tank gets really low.

    Sent from my Pixel XL using Tapatalk
  13. Coral reefer

    Coral reefer President

    I run multi membranes w a booster. Not sure what you are saying exactly tho? I don't have a pressurized storage tank.
  14. tygunn

    tygunn Webmaster

    When I use water from the pressure tank, at some point the RO system starts producing again. If I keep using water from the pressure tank, the pump finally kicks in at some point. I guess I just need to adjust the pressure switch for the pump.

    Sent from my Pixel XL using Tapatalk
  15. Vincerama2

    Vincerama2 Evil Overlord

    This reminds me that I bought a booster pump last year... or was it the year before that? It's still in a box waiting for me to do something with it.

    tygunn likes this.
  16. tygunn

    tygunn Webmaster

    Hah they tend to work better installed.

    Sent from my Pixel XL using Tapatalk
    Coral reefer likes this.

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