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Thread: Is pH supposed to change this much?

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    Join Date
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    Is pH supposed to change this much?

    Have had my pool since 7/4.. Here are my numbers so far:



    My pH after initial fill with city hose water was 7.8.. I was advised to put in 12oz of muriatic acid so I did.. 4 hours after I had put that in I tested pH and it was 7.0.. Next day it was 7.2, next day 7.0, no test, next day 7.0.. I then added 76oz of borax to try and bring it up.. The day after I added the borax I tested and it was 7.8, the next day 7.6, no test, and then today it is 7.2/7.0 (very close - so I guess 7.0)..

    Is pH supposed to change that much?? My FC levels I have been keeping in the recommended levels and my TA as well..

    Let me know your guys thoughts..

    Pool is crystal clear just as an FYI.

    Thanks,

    Tom
    Installed in 2014 - 24' Round x 54" Bliss XL Above Ground Pool 14,090 gallons // Hayward S270T Pro Series 27-Inch 350lb Sand Filter // Hayward SP15922S Power-Flo Matrix Above-Ground Pump 2-Speed //
    Installed in 2015 - Hayward H200FDN Natural Guess Heater // K-2006 Test Kit
    Youngstown, OH 44514

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    JasonLion's Avatar
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    Re: Is pH supposed to change this much?

    That variation is a bit more than what I would expect given your TA level. Everything moves in the expected directions, just a little further than I would expect.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Richard320's Avatar
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    Re: Is pH supposed to change this much?

    Go play around with Effects of Adding Chemicals in poolmath. See what effect CYA has on pH.

    The readings seem to jump a lot more than I would expect, but things do correspond with chemical additions. CYA is, after all, an acid. You added muriatic acid and CYA at almost the same time which accounts for big drops, since the CYA takes time to dissolve. The borax pushed it back up. Then more CYA which is acidic.

    You may be overestimating the pool size and overshooting. Remember to calculate volume by actual depth, not wall height. You haven't gone wildly out of range, so just ease up a little on the pH adjustments and see if things smooth out. You're still in the learning phase, too. You'll get there. In a month's time, it will be as routine as heating a cup of leftover coffee in the microwave. You'll scroll through your post history and cringe. We all do.
    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.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Is pH supposed to change this much?

    Thanks guys.. So adding the additional stabilizer yesterday is most likely the reason for the big drop?

    Should I add some more borax at this point or just let it sit for a few days?

    Oh, and how does one measure actual pool depth? Should I take a tape measure in with me?
    Installed in 2014 - 24' Round x 54" Bliss XL Above Ground Pool 14,090 gallons // Hayward S270T Pro Series 27-Inch 350lb Sand Filter // Hayward SP15922S Power-Flo Matrix Above-Ground Pump 2-Speed //
    Installed in 2015 - Hayward H200FDN Natural Guess Heater // K-2006 Test Kit
    Youngstown, OH 44514

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    Richard320's Avatar
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    Re: Is pH supposed to change this much?

    Quote Originally Posted by tbird2340 View Post
    Thanks guys.. So adding the additional stabilizer yesterday is most likely the reason for the big drop?

    Should I add some more borax at this point or just let it sit for a few days?

    Oh, and how does one measure actual pool depth? Should I take a tape measure in with me?
    7.2 is acceptable. Stop micromanaging. Enjoy a few days' relief. I didn't get in to measure my pool, since I moved in in winter. But, yeah, that's it. Don't let the blade retract until after it dries or the whole thing will rust solid.
    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.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Is pH supposed to change this much?

    Quote Originally Posted by tbird2340 View Post
    Oh, and how does one measure actual pool depth? Should I take a tape measure in with me?
    Quote Originally Posted by Richard320 View Post
    But, yeah, that's it. Don't let the blade retract until after it dries or the whole thing will rust solid.
    Using your net/brush pole, just touch the end to the bottom and grab it at the waterline...then you can just measure from the end of the pole to that spot. Tape measure doesn't get wet and it's a lot easier to try to have a good vertical with the pole (or use a level if you're truly anal about it).
    40x20 IG gunite (~36K gallon). 6' attached spa with spillover. AquaLink RS OneTouch + SpaLink + iAquaLink 2.0
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