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Thread: How long to re-test after adding bleach?

  1. Back To Top    #1

    Join Date
    Jun 2010
    Location
    NW Foothills of North Carolina
    Posts
    21

    How long to re-test after adding bleach?

    I thought that last year I read that you can re-test for FC about 2 hours after adding bleach (in front of returns). If that is true, then I'm getting some good bleach from Dollar General. I tested at 6:00 pm and the FC=2. I added 182 oz of bleach. I re-tested at 9:00 pm, and the FC=9. According to the Pool Calculator, 182 oz of 6% bleach raises FC 4.2.

    I tested at 2 different spots (one in the shallow, one in the deep) across the pool from where I added the bleach.

    The same thing happened when I tested today. Not that I am complaining, but I would like to know if I am actually using stronger bleach than I am paying for, or if I am not waiting long enough for the bleach to circulate.
    21K gallon, 16 x32 IG Vinyl, 3/4 HP Hayward Superpump,
    200 lbs Sand filter, Full sun all day

  2. Back To Top    #2

    Join Date
    Feb 2008
    Location
    Denton, TX
    Posts
    5,061

    Re: How long to re-test after adding bleach?

    About 30 minutes to circulate should be enough.

    What test are you using? Is it the FAS-DPD?

  3. Back To Top    #3

    Re: How long to re-test after adding bleach?

    It could be that your volume is less than 21,000 gallons. If your average depth is 4.5 feet, and the pool is not a full rectangle, then your volume would be closer to 15,700 gallons and the FC would go up by 5.6 ppm by adding 182 ounces of 6 % bleach.

  4. Back To Top    #4

    Join Date
    Feb 2008
    Location
    Denton, TX
    Posts
    5,061

    Re: How long to re-test after adding bleach?

    Quote Originally Posted by JamesW
    It could be that your volume is less than 21,000 gallons. If your average depth is 4.5 feet, and the pool is not a full rectangle, then your volume would be closer to 15,700 gallons and the FC would go up by 5.6 ppm by adding 182 ounces of 6 % bleach.
    +1

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