Tds reading

Discussion in 'Water Fed Pole Cleaning' started by Arnold2408, Mar 23, 2014.

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  1. Arnold2408

    Arnold2408 Newcomer
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    Hi all
    Got all my new equipment set up 3 weeks ago (a 450 GPD ro and a di) and started producing pure water to practice with till I start properly in April. My house tap reading was about 300 so I was pleased when the pure water came out at 000. I didn't use the ro for a couple of weeks but started it going again today and the reading is now 003. After reading this forum I'm sure 003 is ok to use but wondered if there's a reason it's gone up already.
    Any advice would be appreciated. Gonna be unleashing the new system on my customers soon so want it to go well.
    Thanks
     
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  2. Tuffers

    Tuffers Hero
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    How much water did you produce in the couple of weeks when not using the RO? Or did you not produce any water in that time? My guess is that if you did produce water without the RO your TDS of 300 PPM 'burnt' (can't think of a better word) the resin in that time, if you used DI only.
     
  3. Arnold2408

    Arnold2408 Newcomer
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    Sorry I meant that I didn't use the whole system for a few weeks. When using it, it always goes through the RO then a di filter.
     
  4. Tuffers

    Tuffers Hero
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    Try giving the DI vessel a shake.
     
  5. kellyKleen

    kellyKleen Newcomer
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    003 is ok to use but you do not say how much water you produced from your first reading to this last one. I bought some **** resin a couple of years ago and that had to be changed nonstop to keep my TDS down. What is the reading like before the resin and after the RO unit ?
     
  6. brianbadonde

    brianbadonde Member
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    Im going to hazard a guess that you have a very small DI vessel? I started off with a 0.7 litre DI vessel and within a couple of days the TDS went up to 003 ppm. They dont tell you when you buy the equipment that 0.7 is not big enough. Well, it is, but it means you have to keep changing resin! I bought a 7 litre DI vessel and it has lasted 3 months and is still producing water at 002 ppm. When this gets abobe 3/4 ppm im going to hook this vessel up to a second DI vessel so the resin in the second vessel lasts longer. When this then goes too high in regards to TDS im going to replace the resin in the first vessel, then swap the vessels around. This way you get maximum use from your rein and save a few £s. So ive been told.........
     
  7. spruce

    spruce Grand Master
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    Your r/o membranes won't be producing pure at 100% efficiency.

    If your tap water tds is 300 then your tds output will be 6 at 98% efficiency. The last 6 ppm will be removed by the resin in the di vessel.

    As has been stated by other posters the tiny di vessel that is sometimes used with RoMan type filters is too small. To understand how your r/o is actually performing you need to take a sample of the water quality taken after the r/o membranes but before the di. The higher the tds of the pure, then the less efficient the r/o is working.
    97 to 98% would be what these should run at.
     
  8. Arnold2408

    Arnold2408 Newcomer
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    Thanks for your replies. The tds reading is now up to 007 after going through the ro then the di.
    I phoned the supplier of the RO as I'm new to all this, for advice. He got me to take a reading of the water after the RO but before the DI. This reading was 021. He was then able to tell me that I needed to change my resin. Apparently the resin is only good for about 600 litres if the reading after the RO is 021. This means I will be having to change the resin very frequently. Shall I buy loads of resin or get a bigger DI ?
     
  9. Tuffers

    Tuffers Hero
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    What size di have you got Arnold2408 ? If it's smaller than 11L I'd get 11L at least.
     
  10. Arnold2408

    Arnold2408 Newcomer
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    Its a 10" complete DI resin filter unit. I think it holds 700ml of resin. Got it along with my RO unit.
     
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