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Thread: Abnormal FC drop?

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    Abnormal FC drop?

    I've had a target of 8 for my FC for the last week or so and it has been dropping to 6 or so, yesterday it only dropped to 7 or 7.5 but was an overcast day. Today it was around 90 and pretty windy, also the first day the kids got in for a couple hours and when I checked it this evening it was down to 4. Is this normal for it to drop that much in a warmer, windy day? The pool calculator had me put 142 oz. in today, at that rate I'm going to have to have a bunch of bleach on hand!!!

    Thanks for any input anyone may have.
    27' round Above ground w/sand filter
    17100 gallons calculated
    Nashville, IL

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    Richard320's Avatar
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    Re: Abnormal FC drop?

    2 ppm/day isn't extreme.

    If those kids were dirty, or someone took a leak in the pool, that can account for the jump in demand. Wind will also blow more organic debris into the pool, even small stuff you can't see easily, like pollen, which will consume chlorine as it gets oxidized.

    There's always the OCLT to see if there's trouble brewing.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
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    Join Date
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    Denton, TX
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    Re: Abnormal FC drop?

    Quote Originally Posted by Richard320
    There's always the OCLT to see if there's trouble brewing.
    That;s what I would try, just to be sure.

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    duraleigh's Avatar
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    Re: Abnormal FC drop?

    The extra heat and the kids can easily account for that drop. Over the summer, most pools seems to average a 2-3ppm drop daily.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Abnormal FC drop?

    Thanks guys for all the feedback. That is what I expected the replies to be but just wanted to make sure. I just tested FC and it's at 10 this morning and pH is 7.8. We did have a lot of flying debris, grass, pollen, and such in the pool yesterday as well as a large intertube that I use to keep the pool cover elevated in the middle during the winter. No doubt that thing had some remnants of nastiness on it even though we wiped it off with a wet cloth before putting it in the water.

    Thanks again forf all the help! This forum is awesome!
    27' round Above ground w/sand filter
    17100 gallons calculated
    Nashville, IL

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