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Thread: Will pH Read High with High FC And High CYA

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    Will pH Read High with High FC And High CYA

    I was surprised that my pH seem to rise dramatically over a couple weeks, after raising the chlorine due to high CYA. I was also trying to get rid of some algae. At the same time, I got the pool pump system working better with better flow, so the spillway for the spa started working. Now I am not sure if I am reading high pH due to higher FC, or it is due to more aeration from the spa spillway. Will you get a different reading for pH with a pool with high FC and low CYA, and a pool with high FC and high CYA. I am not sure if I should be adding acid or not.

    FC 25
    CC 0
    CH 750
    TA 190
    CYA 120
    pH 8.2
    Michael

    20,000 gallon in-ground gunite/plaster pool (1992), attached spa with spillway, Pentair Superflo 1.5 HP pump, Smith booster pump for pool sweep, Pentair 2000 DE filter, Sta Rite Max-E-Therm 400 heater, Silencer Blower 2 HP for spa, Polaris 280 pool sweep.

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    Wildcat's Avatar
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    Re: Will pH Read High with High FC And High CYA

    Aeration will raise PH
    High FC leads to false high PH readings

    From what others have said, complete your SLAM, reduce FC to 10 or below and then adjust your PH

    What was PH before the SLAM?
    10000 Gal, IG Pebbletec, pop up cleaners,Hayward EcoStar VS, 425 sq ft Hayward Cartridge, waterfall feature

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    Mod Squad pooldv's Avatar
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    Re: Will pH Read High with High FC And High CYA

    Correct. PH test is not valid when FC is over 10. Finish the slam and retest PH after FC is under 10. CYA does not affect PH.
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    Re: Will pH Read High with High FC And High CYA

    Quote Originally Posted by Wildcat View Post
    Aeration will raise PH
    High FC leads to false high PH readings

    From what others have said, complete your SLAM, reduce FC to 10 or below and then adjust your PH

    What was PH before the SLAM?
    pH was 7.8 before SLAM.

    Can an accurate reading be had if a chlorine neutralizer was used during the pH test?
    Michael

    20,000 gallon in-ground gunite/plaster pool (1992), attached spa with spillway, Pentair Superflo 1.5 HP pump, Smith booster pump for pool sweep, Pentair 2000 DE filter, Sta Rite Max-E-Therm 400 heater, Silencer Blower 2 HP for spa, Polaris 280 pool sweep.

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    epro05's Avatar
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    Re: Will pH Read High with High FC And High CYA

    No, that won't work.
    27,500 gallon in ground gunite/plaster (1995). Attached Spa with fountain, spillway, and 2 lion heads streaming into the pool. Hayward pump and AO Smith UST1152 1.5 hp motor (single speed). Hayward 60 sq ft DE Filter (Model DE-6000). Kreepy Krauly cleaner.

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    Richard320's Avatar
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    Re: Will pH Read High with High FC And High CYA

    Quote Originally Posted by epro05 View Post
    No, that won't work.
    To expand:
    Accurate pH test during shock levels with R-007?
    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.
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    epro05's Avatar
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    Re: Will pH Read High with High FC And High CYA

    Thanks Richard, I just spent the last 10 minutes looking for the very post you linked. I had those pictures in mind which I said "No, that won't work", but felt I needed to back it up with some evidence.
    27,500 gallon in ground gunite/plaster (1995). Attached Spa with fountain, spillway, and 2 lion heads streaming into the pool. Hayward pump and AO Smith UST1152 1.5 hp motor (single speed). Hayward 60 sq ft DE Filter (Model DE-6000). Kreepy Krauly cleaner.

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    Re: Will pH Read High with High FC And High CYA

    Great information, guys! It looks like it is another reason why it is hard to operate a pool with a high CYA. You need higher FC even without a SLAM, but then the pH reading becomes distorted.

    I'm learning so much here. Thank you very much!
    Michael

    20,000 gallon in-ground gunite/plaster pool (1992), attached spa with spillway, Pentair Superflo 1.5 HP pump, Smith booster pump for pool sweep, Pentair 2000 DE filter, Sta Rite Max-E-Therm 400 heater, Silencer Blower 2 HP for spa, Polaris 280 pool sweep.

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