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Thread: No chlorine in salt water pool! Test positive for phosphates and nitrates

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    No chlorine in salt water pool! Test positive for phosphates and nitrates

    Because my salt water pool was not producing chlorine, the pool store tested the water for phosphates. It said it had 300 ppm. They sent me home with a phosphate remover. I waited 72 hrs and back washed the DE filter, even though the pressure never went up. I brought a sample in again, and this time there were 500 ppm!!! He had me double dose the pool with a remover. Pressure never rose, but backwashed as indicated. Phosphate level remained at 500ppm!!
    They tested for nitrates. It came back at 26 ppm. I was told to empty the pool water down to a foot in the low end.
    Do I have to??!!! Is this the only alternative?!! I have a month left before we close the pool for the winter. I would hate to pay for new water and salt, only to drain the pool again in a month for winter!!!!
    Help please!!

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    JasonLion's Avatar
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    Re: No chlorine in salt water pool! Test positive for phosphates and nitrates

    Welcome to TFP!

    Neither phosphates or nitrates matter. Both are algae food, but if you have chlorine in the water the algae will all be killed regardless.

    Most SWG problems are caused by chemical levels being out of balance. Could you post a complete set of test results?

    It is also possible there is a hardware problem of some kind. Do you have any error lights or error messages on the SWG?
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: No chlorine in salt water pool! Test positive for phosphates and nitrates

    Quote Originally Posted by gratefuldog View Post
    Because my salt water pool was not producing chlorine, the pool store tested the water for phosphates. It said it had 300 ppm. They sent me home with a phosphate remover. I waited 72 hrs and back washed the DE filter, even though the pressure never went up. I brought a sample in again, and this time there were 500 ppm!!! He had me double dose the pool with a remover.
    Wow. When the test results didn't make any sense, he just doubled down. Ignore the phosphates and get a proper chlorine to CYA ratio and you'll do fine. While I wouldn't trust their results, what are your stats? Especially that CYA/stabilizer?

    It would be good to get your generator going, but I have no advice on that. I don't have one.

    While it will take a bit of reading to get up to speed, you can just add liquid chlorine (aka bleach) for a month until close. If you're going to drain anyway, you could probably use trichlor pucks. The build up of CYA won't be bad in one month. The point is, you have lots of alternatives, but you'll need to read up in "Pool School" to understand them.
    20,000 gal in-ground plaster pool with sand filter. Replastered recently. Mostly adding bleach and acid. CYA was high when I took over.

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    Re: No chlorine in salt water pool! Test positive for phosphates and nitrates

    Results from a week ago when discovered:
    Free chlorine 0 ppm
    total chl .01 ppm
    combined .01 ppm
    pH 7.8
    alkalinity 80ppm
    hardness 180ppm
    cyanuric acid 5 ppm
    phosphate 300ppm
    salt 3000

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    Re: No chlorine in salt water pool! Test positive for phosphates and nitrates

    just wanted to add that the pool looks great. No signs of algae.

    - - - Updated - - -

    no error messages. All lights are green on SWG

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    Re: No chlorine in salt water pool! Test positive for phosphates and nitrates

    From those test results I will offer this:

    1. The cyanuric acid level is low and the sun is burning off the chlorine.

    2. Algae has started and the SWG can not make enough chlorine to get ahead of the algae. The chlorine is used up killing off the algae before it registers in the pool. It is very common that SWG users do not see visible algae as the SWG is making just enough chlorine to prevent the algae from blooming.

    You do not need to drain the pool, but you do need to go through the SLAM Process. Please read the following links and ask questions if needed.

    http://www.troublefreepool.com/conte...ater-chemistry
    http://www.troublefreepool.com/conte...generators-swg
    http://www.troublefreepool.com/conte...tain-shockingl
    16k gal plaster with raised spa, Jandy DEV60 filter, 2 HP 2-speed SHPF Jandy Stealth pump
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    Re: No chlorine in salt water pool! Test positive for phosphates and nitrates

    I will add that it will be impossible to follow the SLAM process without your own proper test kit. If you want to take control of your pool, you will need a TF-100 or K-2006. Link is in my signature.
    John
    7 year old ~13,500 gal 24' AGP with 1.5 hp Proline pump, 150 sqft Pleatco cartridge, filled with well water with pH of about 4.5.
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    Re: No chlorine in salt water pool! Test positive for phosphates and nitrates

    Welcome to the forum

    Those pool store numbers just don't seem right. I don't think they can test accurately to .01 ppm in chlorine or 5ppm in CYA. Most test kits have 20 as the low limit on the CYA test and most FC is red in .5 increments.
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