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Thread: FC Drop test and results

  1. Back To Top    #1

    Join Date
    Jul 2010
    Location
    Central Illinois
    Posts
    40

    FC Drop test and results

    When doing the drop test for FC, I get to a certain spot and the water will go clear, but then back to red a little. Does the measurement count when it first turns or when it stays. Just wanna make sure on it.
    18' x 54" Round AGP, Hayward pump/Cartridge Filter, 8 Gallon Liquidator, and TF-Test

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

    Re: FC Drop test

    It should turn clear and stay clear for at least 15 seconds. If it turns pink again more quickly than that, add another drop. If you leave the sample sitting still for a couple of minutes it will almost always turn pink again, and the same thing can happen during the test if you do the test way too slowly, like say taking a phone call in the middle of the test.

    The main case to watch out for, is if you have a very high CC level, you need to do the test fairly quickly, or there will be some ambiguity. CC can "leak" through into the FC portion of the test if the CC level is high and you go too slowly on the first phase of the test.
    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
    Jul 2010
    Location
    Central Illinois
    Posts
    40

    Re: FC Drop test

    TY Jason!!
    18' x 54" Round AGP, Hayward pump/Cartridge Filter, 8 Gallon Liquidator, and TF-Test

  4. Back To Top    #4

    Join Date
    Jul 2010
    Location
    Central Illinois
    Posts
    40

    Re: FC Drop test and results

    last night numbers 9PM
    FC 12
    CC 0
    PH 7.6
    TA 100
    CH 220

    This morning 6AM
    FC 12
    CC 0
    PH 7.6
    TA 100
    CH 220

    The pool has been open for a week now, I think that I'm good to go with my numbers. I need to just fine tune the LQ
    18' x 54" Round AGP, Hayward pump/Cartridge Filter, 8 Gallon Liquidator, and TF-Test

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