RO filter TDS readings

Discussion in 'Water Parameters and Additives' started by ziguri, 29 May 2015.

  1. ziguri

    ziguri

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    Recently i bought a new membrane for my RO/DI filter, as well as a TDS meter. I disconnected the Resin chamber, inserted the new membrane and flushed it for around an hour or so. I then tested the water which was coming out and it gave me a 0ppm reading. I then connected the Resin chamber and started filling a drum, which i filled halfway. When i tested the water in the drum , it gave me a 14ppm reading... What would be the cause of this, is it perhaps something to do with the resin, or maybe the drum i used was not rinsed and still had some salt/dirt inside?
     
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  3. 459b

    459b Moderator MASA Contributor

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    probably dirty drum
    measure the tds as it comes out the unit and see if its different to whats in the drum
     
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  4. ziguri

    ziguri Thread Starter

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    Will do that when i get home, hopefully just a dirty drum then :)
     
  5. Rors

    Rors

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    I agree, 14 is pretty high even for RO water, I rate its the drum, that needs a good clean with RO Water As normal tap water will leave behind unwanted elements. Good luck
     
    Last edited: 29 May 2015
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  6. Quintus

    Quintus the irish aXeman

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    are you talking about 14 ppm in tapwater? never, unless this 14 is a filtered reading from tap

    even in the States the average is between 60 to 140ppm TDS depending where
    the tap water from my house is 112ppm
    my borehole give me 84 average , these readings are before RO
     
    Last edited: 29 May 2015
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  7. zippy

    zippy

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    if it isn't the drum it clears out after a bit, if I bump my RO unit i get a few minutes of 2-3ppm water instead of 0ppm, after I swopped all my filters out 6 months ago it took about 1000l of about 9ppm to 3 ppm, eventually it cleared again. I also asked the manufacturer, unfortunately they didn't have an answer for me. I was also concerned.
     
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  8. Nemos Janitor

    Nemos Janitor

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    How much RO water is being made at a time?
     
  9. ziguri

    ziguri Thread Starter

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    the most I make at a time is 100 liters. I made around 50 or less last night when it gave the 14ppm reading. Other than that the only times I make 5 or 10 liters. I also flush for about 2 minutes weekly
     
  10. Nemos Janitor

    Nemos Janitor

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    Yes membranes that are used to make small batches of water and that are infrequently used can shorten the lifespan of the membrane.

    What resin do you have in the resin chamber?

    Did you replace the carbon block and sediment filters?
     
  11. shaunn

    shaunn

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    just my 2 cents my tap water is 120 tds and the borehole is 54 tds note the borehole is uncased and 100m deep
     
  12. ziguri

    ziguri Thread Starter

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    I replaced the 2 pre filters a few months back. Using the resin from Waterboy
     
  13. Nemos Janitor

    Nemos Janitor

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    And the resin? When did you replace that? Has it gone brown?
     
  14. ziguri

    ziguri Thread Starter

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    I replaced yesterday. I used a little that i had left over (pack was re-sealed properly) and filled the rest with some new resin i bought. It did look though like the older resin was a little drier than the new resin, but not much really. It is all still a bluish colour
     
    Last edited: 29 May 2015
  15. Nemos Janitor

    Nemos Janitor

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    Sounds all good. Next time you make water, flush the system, then run through about 10L, Discard that 10L, then test the TDS of new water.

    You did check the calibration of you TDS meter?
     
    Last edited: 29 May 2015
  16. ziguri

    ziguri Thread Starter

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    Nope, how do you check calibration? Tap water gave mee 114ppm reading, waste water gave me 166ppm . I got a 0ppm reading before i hooked up resin chamber. I will still take a small sampleof new water later and test.
     
  17. Nemos Janitor

    Nemos Janitor

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    Give Marco a call. He has the calibration fluid.
     
  18. ziguri

    ziguri Thread Starter

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    OK cool, i will test water later again first,plus the tds meter is new
     
  19. Nemos Janitor

    Nemos Janitor

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    Any measuring equipment needs to be calibrated before use. New or not. You could be chasing your tail.:thumbup:
     
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  20. ziguri

    ziguri Thread Starter

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    Looks like it's just a dirty drum. I made water in other containers all with zero ppm readings . Will rinse the drum nicely over the weekend
     
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  21. Bendor

    Bendor

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    Love my tds meter, Saved me lots of money with regard to RODI filters. Would have exchanged mine loooooong ago.
     
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