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Thread: FC decrease question??

  1. Back To Top    #1

    Join Date
    May 2007
    Fayetteville, Arkansas

    FC decrease question??

    Here are numbers from this morning:

    FC 1.5
    PH 7.8
    TA 70
    CYA 50

    I'm getting an avg of 4ppm FC decrease each day, down from 5. There is no CC and the pool is sparkling with no visible signs of algae. I'm brushing about twice a week and the pool gets a very hot 8 hours of sun daily. There has been minimal use of the pool the last few days during this observation.
    With the CYA at the high normal end of the TFP recommended scale, should I expect a 4ppm FC drop given the conditions outlined?

    Thanks a lot everyone ... hope your summer is going great!
    20x40 30,000 gal IG Liner, Pentair II Sand

  2. Back To Top    #2
    reebok's Avatar
    Join Date
    Apr 2009
    Lakeland, FL

    Re: FC decrease question??

    possible. you can try a cya of 60 to help some. I would try an overnight fc loss test just to make sure nothing's growing.
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

  3. Back To Top    #3
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: FC decrease question??

    With a CYA of 50, I would expect FC to fall by 40% to 60% through a sunny day. If you started at 6.5 and fell to 1.5 then that is more of a drop than I would expect.
    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

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