How To Test Your Ro Rejection Rate

Discussion in 'Water Fed Pole Cleaning' started by David Taylor, Mar 9, 2013.

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  1. David Taylor

    David Taylor Well-Known Member
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    (tap tds - RO tds) divided by tap tds x 100
    90 1 = 89 90 = 0.98 98.89%




    If your RO falls below 80% it time for a new one


    DO not have your DI in line.

    Edited for spruce who likes to be exact so i added the 0.89%
     
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  2. spruce

    spruce Grand Master
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    Your efficiency is closer to 99%.

    Personally I replaced my membranes before that. As they become more inefficient with age, your resin costs will increase.

    We have the di vessel after the membranes and then process pure into the IBC tank. The reason why we do this is because 3 of us use the water = 1 di vessel not 3.

    At the moment there is no need for you to connect the di vessel up as cleaning with a tds of 1 will be fine. I would only start to add a di vessel when the water purity gets to 4. But then that's me and it's up to you and how you feel.
     
  3. David Taylor

    David Taylor Well-Known Member
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    Well they say change at 90% but 80% is a must, after this your wasting your time.

    It was just so people could check how their RO was performing.

    I have a small 10 inch DI vessel after 2 x 40 inch, but like you i don`t need to use it really.

    Static RO system connected to van at night so pure str8 into 900lt van tank
     
  4. OoO

    OoO Guest

    98.52% yay lol
     
  5. David Taylor

    David Taylor Well-Known Member
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    So would I personally....
     
  6. Smurf

    Smurf Banned
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    If I used that method (if I had a 900 ltr van tank) my van would be sat on the driveway (if I had a driveway) for approx 48 hours waiting for it to be full using my 300 gpd ro :D

    Unless you use a lot of water each day (800-900 ltrs) why do you have such a big tank?

     
  7. David Taylor

    David Taylor Well-Known Member
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    2 ppl can easily use 400 litres each per day, I like quite high flow rates.

    my twin 40 makes it like i`m filling it from the tap.
     
  8. Matty H

    Matty H Forum Addict
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  9. spruce

    spruce Grand Master
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    :D

    89 divided by 90 x 100 = 98.88889% efficient

    To check. 100 tds in - 98 out is 98% efficient - easy to work out in your head. On a calculator 98 divide by 100 x 100 = 98%.

    Apply the same 'formula.'
     
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