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Thread: Mystery

  1. Back To Top    #1

    Join Date
    Aug 2012
    Location
    Fort Worth, TX
    Posts
    83

    Mystery

    Several nights ago, I topped my FC off to 8 ppm.
    I usually do it every other day. It was reading 2.5 which is abnormally low. I tested it twice from water at different places in the pool.
    I added 10 cups of 8.25 bleach. So far so good.

    The next morning I tested again and read 14 ppm. I tested twice more and read the same thing.
    I had used a new bottle of bleach. I shook it and it had about what would be expected with 10 cups gone.
    I had not mistakenly added bleach twice the night before.

    That night it read 9 ppm. That is a loss of 5 ppm which I have never witnessed before.

    Over the next few days it behaved as it always has- no strange readings.

    To save my life, I can't explain what happened. Bad tests is the only possibility and I double and triple checked them.
    10,000 gal / Plaster / Cartridge Filter / 1 1/2 HP pump motor/ TF-100 test kit.

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Mystery

    FC going up to 14 is a mystery. Nothing comes to mind.

    FC loss is always a percentage of the starting level, so it is normal that you will lose more FC when the starting level is higher.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  3. Back To Top    #3

    Join Date
    Jun 2014
    Location
    Central Florida
    Posts
    36

    Re: Mystery

    I wonder if it is ever the case for a bottle of bleach to be an abnormally higher % than the label says.
    22,000 gallon in ground, gunite, Hayward pump 1.5 hp and 36sq DE filter. Pool installation date unknown, at least 10 years. Screened enclosure.

  4. Back To Top    #4

    Join Date
    Aug 2012
    Location
    Fort Worth, TX
    Posts
    83

    Re: Mystery

    That's what I wondered.
    After using the rest of that bottle, it appears to be the correct strength.
    10,000 gal / Plaster / Cartridge Filter / 1 1/2 HP pump motor/ TF-100 test kit.

  5. Back To Top    #5

    Join Date
    Aug 2012
    Location
    Fort Worth, TX
    Posts
    83

    Re: Mystery

    error post
    10,000 gal / Plaster / Cartridge Filter / 1 1/2 HP pump motor/ TF-100 test kit.

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