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Thread: why the jump from FC 4.5 - 7.5?

  1. Back To Top    #1

    Join Date
    Jan 2011
    Huntsville, AL

    why the jump from FC 4.5 - 7.5?

    Last week my number were:
    FC = 4.5
    ph = 8
    TA = 90
    CYA = 40

    I made (or tried to make) a few adjustments suggested by Jason over the last week and ended up today with:
    FC = 7.5
    Ph = 7.5
    TA = 70
    CYA = 50

    I overshot the trying to lower the PH with MA and had to counter with Mule Team 20. My question is why the big jump in FC?
    It has been hot and plenty of sunlight. I have not changed my SWG and it is at 60% and runs from 10:15 am to 5:30 pm

    Is the time of the day that big of a difference? The second test with the high FC was first thing in the morning in the shade, no
    Swimmers, and swg off.

    The algae nightmares have me very hesitant to reduce the swg percentage, but it really looks like I need to?? I will also retest CYA later this week and add more to get closer to the pool school recommended level.

    Thanks again.
    16 x 32 inground with Tara Liner, 1 skimmer, 3 returns,
    1HP Hayward Super Pump
    Hayward Sand Filter
    Polaris 280 w booster pump
    Hayward SWG & Aqua Plus
    k-2006 Test Kit

  2. Back To Top    #2
    Richard320's Avatar
    Join Date
    Jan 2010
    San Dimas, CA (LA County)

    Re: why the jump from FC 4.5 - 7.5?

    You probably killed off something that was consuming your chlorine. And you added CYA, which saves it from the sun. If it keeps going up, you just need to turn down the SWG a little at a time until you reach the magic number.
    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.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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