What should pre resin TDS level be??

Discussion in 'Water Fed Pole Cleaning' started by Mooners, Aug 23, 2015.

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  1. Mooners

    Mooners Member
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    Hi All,

    i've a Pure Freedom Van mounted set up with a couple of 20inch pre filters & ro unit and di vessel.

    Only using 2000 litres a week at the mo. I had great TDS levels for a ages then as they crept up I changed the resin. After a couple of weeks this started to creep up again and now a reading of TDS reading of 10:(

    Just trying to troubleshoot really. I'm getting a reading of 32 before the DI vessel. Is this good or bad? How often should the pre-filters be changed. I've ordered some new ones though some confirmation on what readings should be throughout the system would be appreciated. Tap water 272 down on the South Coast.
     
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  2. doug atkinson

    doug atkinson Well-Known Member
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    Your membrane is only giving you 89% rejection rate so is on its way out. You should also notice a drop in production.

    Pre-Filters should be changed dependent on specification of the filter, for example some will do 10,000 litres, others 28,000 litres and so on.

    Check your riser tube has not gone oval in shape.

    What grade resin are you using.
     
  3. shazzy692002

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    My tap water is 280, after ro b4 resin it used to be 9 but not 20ish. I need to change my sediment etc to bring it back down. . it just mean I use more resin.
     
  4. Mooners

    Mooners Member
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    Thanks for the info doug.

    Another question for you, how do you determine if it's just the filters that need changing or the ro membrane?

    I was hoping the membrane would have lasted me a bit longer than 6 months at part time.

    Am using Tulsion MB-115 Resin

    big thanks


    Matt

     
  5. spruce

    spruce Grand Master
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    As Doug has said, certain carbon block filters last longer than others.

    A GAC carbon block only has a service life of 2500 gallons; around 10000 liters. If you have a 4040 r/o set at 50/50 waste to pure ratio, you will only produce 5000 liters of pure before the GAC filter has finished it service life.

    So if you are using 2000 liters of pure a week, then you should be changing that carbon block every 2.5 weeks. If the manufacturers service life forecast is correct then only after 2.5 weeks you are now putting your r/o membrane at risk of damage from chlorine.

    The Fiberdyne 20" carbon block filters we use are good for 78000 liters - so at 50/50 pure to waste ratio we can get 38000 liters of pure. We have to change filters every 3 months.
     
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  6. Duncs

    Duncs Grand Master
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    i was ordering pre filters this week resin not lasting at all at moment
    was cracking to the very helpfull guy at pure freedom
    thinking at back off mind the membrane was on way out
    with his advice he said the membrane was right enough basically
    knackered
    But he said changing the pre filters wouldint help with how long my ressin was lasting becourse the membrane was knackered
    so will wait and change both together , but really my own fault did,int change thge pre ilters enough ( tough lesson learned £200 for membrane )
     
  7. Mooners

    Mooners Member
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    Thanks Spruce for your words of wisdom. After doing a search of the Fiberdyne carbon block filter I came across a previous post on here from yourself which helped further. Filters ordered, and hopefully will get them in tomorrow.

    Duncs, i may be in the same situation as yourself:(

    Do you guys have an inline water meter in your set up so you can keep tabs on what you're using?
     
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