Tds Reading After Membranes

Discussion in 'Water Fed Pole Cleaning' started by charlie tapper, Aug 1, 2013.

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  1. charlie tapper

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    hi

    what is a good tds reading after the membranes ?

    i have 014 ... is that good ??

    cheers
     
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  2. David Taylor

    David Taylor Well-Known Member
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    depends what you start with, it`s worked out in a rejection percentage, above 95% is good.....


    so if you start with 100 your looking for 1ppm to 5ppm with a new membrane... that is 99% to 95%


    other factors will come in to play like pressure at the RO and temperature.
     
  3. charlie tapper

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    if i have worked it out correct mines 93 %
     
  4. David Taylor

    David Taylor Well-Known Member
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    is your water 200 ppm?
     
  5. rcproperty

    rcproperty Hero
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    my water starts at 450ppm then out of RO at 012-016ppm
     
  6. charlie tapper

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    yeah sorry its 216
     
  7. rcproperty

    rcproperty Hero
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    for only starting at 216 then you should get lower than your getting out, would of though it should below 010ppm
     
  8. OoO

    OoO Guest

    440ppm - 7ppm ;)
     
  9. spruce

    spruce Grand Master
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    Hi Charlie

    You haven't given us any detail with regards to what r/o it is. It can't be a Merlin r/o as that would be around 90% when new.

    So IMHO your membrane/membranes probably need replacing. If you have one of those RoMan type r/o with several membranes, then it could be 1 membrane that is the culprit. I would try to identify it by coupling up each membrane to work individually and test each one. We were told (by Peter Fogwill) that these type of membranes should work at between 97 - 99% efficiency, anything less than that is wasting resin polishing the water off. This was our experience with a 450GPD 3 membrane r/o we had. Membranes worked at that effieceiency for 6 years before failing. We have now upgraded to a 4040 and that is working at 98 to 99% efficiency and its a year old now.

    If they have been in for a while, then I would replace them all anyway.
     
  10. charlie tapper

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