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Thread: Pool tests of PH changed color

  1. Back To Top    #1

    In the Industry
    Masspools's Avatar
    Join Date
    Jan 2013
    Cambridge Massachusetts

    Pool tests of PH changed color

    Hi All

    I have tested the pool water at commercial pool using our standard test kit. The reading from PH registered as 7.4, then the color of the tested water gradually changed to purple. Why would it do this?

    Salt pool
    34,333 gallons
    ORP 840
    Cl 5
    83 degrees

    Update: people have mentioned there lips are burning and rashes.

  2. Back To Top    #2
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Tucson, AZ

    Re: Pool tests of PH changed color

    Here are some extended instructions:

    The pH test should be read immediately and then it is not uncommon for it to drift up. FC > 10ppm can also make it drift up.

    What test kit are you using? Looks like your CL is at the top of your range probably right?

    We would need a full set of test results to better guess at what is going on:
    Jason, TFP Moderator
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  3. Back To Top    #3
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Pool tests of PH changed color

    I suspect that your FC level is very very high and you are not using CYA.

    An ORP of 840 is exceedingly high. Plus, the PH test turns purple when the FC level is very very high, typically at FC levels over 20.

    Most likely the high FC level is the result of using a SWG too much on an indoor pool.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  4. Back To Top    #4

    In the Industry

    Join Date
    Oct 2012

    Re: Pool tests of PH changed color

    I agree with everyone else. What does your free chlorine read? If it begins to turn pink and then is way too high.
    24' round above ground, 13500 gallons, vinyl liner, 18" Sand Filter

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