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Thread: Not sure about pH reading?

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    Not sure about pH reading?

    I own a 17,500 gallon inground fiberglass pool in South Arkansas. Due to the cooler weather, I've been slacking with my tests. The other day I decided to test my pH and I got a very reddish that doesn't fit into the color spectrum on the test vial. I assumed my pH was extra high, so I started adding muriatic acid. To make a long story short, I've added almost a full jug (the one from Home Depot that comes in packs of 2) and I'm still getting that same color. Is it possible that my pH is still high and I need to continue adding acid, or is there something else throwing my test completely off? I've never had this problem before and have always gotten a reading that falls within the color spectrum.


  2. Back To Top    #2

    Re: Not sure about pH reading?

    Is it possible that your testing chemicals where compromised?

    What test kit do you use?
    Austin, Texas
    30,000 gallon Gunite/Pebble
    Pentair Clean and Clear Plus CCP 520 Cartridge 150GPM
    Pentair Whisperflo WF-28 2HP Pump
    Delzone Eclipse 4 Ozone Generator

  3. Back To Top    #3

    Re: Not sure about pH reading?

    Shouldn't be the case...I've used two different brands of the 5-Drop pH tester...Taylor R-0004 and an off-brand from the Pool Shop. The results were the same.

  4. Back To Top    #4
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Not sure about pH reading?

    What is your FC level? When FC is around 20 or higher the PH test result can be completely invalid. PH results can also be somewhat off when FC is between 10 and 20, but above 20 PH results are completely useless (and strangely colored).
    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

  5. Back To Top    #5

    Re: Not sure about pH reading?

    FC is 5.


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    Re: Not sure about pH reading?

    What is your TA (Total Alkalinity)?

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    Join Date
    Jul 2011
    Central Califorina

    Re: Not sure about pH reading?

    A full set of test results will help us help you. As stated TA will come into play with PH. Also if your HD sells the kem tek MA like mine its half strength 15%.
    3500 gallon 14x42 Intex Ultra Frame
    1/2 HP Intex 1600 sand filter/pump - Intex SWCG
    Two 4x20 Fafco solar panels.
    Taylor K-2006
    Marquis spirit hot tub - Grill Dome ceramic grill/smoker

  8. Back To Top    #8

    Re: Not sure about pH reading?

    I got a full set of results this afternoon:
    CYA 50
    TA 110
    FC 4
    CC .5

    And I'm still getting that unrecognizable red color on my pH test...and I've used one full jug of 20 Baume 31.45% Muriatic Acid from Home Depot. I'm really lost on this one?? Any ideas? I'm not sure if I need to continue to add MA?


  9. Back To Top    #9

    In the Industry
    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: Not sure about pH reading?

    Why not scoop up a plastic pail of pool water and add a little acid at a time to see if you can get the colors into the normal range. That'll give you some confidence that you are applying the right chemistry....just not enough of it yet.

    The pH test is pretty reliable if your testing chemistry is OK. It's been kept out of the sun, right?
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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