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Ro unit reading high tds

Discussion in 'Tank Mods & DIY' started by simon1987, Jun 19, 2016.

  1. simon1987

    simon1987 Registered

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    I bought a ro unit. A three stage one. All set up, and running at just under 3 bar. I noticed the reading of tds been about 30 still, so bought a di ionisation chamber to add on and make it a 4 chamber system. I have run the system for about two hours to clean out the unit, and binned that water. The clean water outlet is still running at about 25 ppm tds. Is this bad, as I've read it should be zero. I tested the ro water I buy from my lfs and that reads 31 tds. Any advice would help as I'm new to producing water myself, but think it would be easier making it myself instead of going and buying it all the time.


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  2. chippypah

    chippypah Registered

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    Yes should read 0, sounds like something not set up right.
     
  3. Sabaxter

    Sabaxter Registered

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    Which brand is your ro unit. Pressure shouldn't affect the quality of water just the production rate.

    When I test I get a cup fill it with ro put the meter and give it a good stir and throw it away. I then fill again insert the tds and take that reading.

    I've been doing ro tonight, normally my meter reads 23-26 but Ince rinsed I get an accurate reading and mines currently at 002tds so next time I will change my media in the top chamber (can't think of the name) this will then Polish it back to 000 tds

    Hope this makes sense
     
  4. gary66

    gary66 Registered

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    Ask your LFS what TDS they are reading. Sounds like your meter is giving an incorrect reading if their RO is high also. LFS ro water should be zero
     
  5. spiritwalker

    spiritwalker Registered

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    Test at source just putting RO in a container changes readings I was getting different results from lfs to home just from filling up a brand new clean as a whistle 25lt barrel .i now make my own and reads 000 at end of pipe from RO unit . I then test in a clean rinsed in RO whiskey glass after that there's not a lot you can do about increased readings unless your using a glass container to transport your water that's been cleaned in a steam oven lol .I have a 200 lt water butt mixing salt and have 100lts of RO in 25lt containers but I bet if I check my RO in containers it won't read 0 .Also note if you have auto top up containers they need regular cleaning as same problem happens here .
     
  6. trumpet30

    trumpet30 Registered

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    I have a three stage unit also but owing to my water TDS being high to start i was getting a final reading of 14. I added a DI resin pod as the final part of the system and hey presto 0 TDS.


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  7. jim_fitz

    jim_fitz Admin Staff Member

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    try testing your tds meter against your lfs'

    might need calibrating
     
  8. spiritwalker

    spiritwalker Registered

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    So might there's the only true way would be to spend 1000s on a medical lab grade type set up . Mines a hm one and brand new so I'm happy with it for now
     
  9. steve861uk

    steve861uk Registered

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    I go through a process of dip-stir-dip-remove-flick and shake with my TDS meter (repeated a couple of times). Residual left over water from previous tests can affect the reading sometimes.

    Make sure you flush your membranes regularly and always use DI resin as the final chamber to ensure nicely polished water (the DI resin will have to be changed regularly as it soon expires - I do mine every couple of weeks or so) :)
     
  10. cuprajake

    cuprajake Registered

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    we have an inline tds meter on the output of our line,
     
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