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Thread: Water balance testing

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    Water balance testing

    Using TF-100 and salt strips I got the following numbers a few days ago
    PH 7.8
    FC 5
    CC 0
    TA 90
    CH 310
    CYA 80
    Salt 3550

    Pool store results from today.
    FC 3.4
    ph 8.0
    Alkalinity (w stabilizer correction) 26
    CYA 80
    Salt 3000

    Pool store recommends adding 38 pounds of baking soda because alkalinity level is low (26). Recommended range is 80-120. But own test results for TA is 90.

    Do I add or not add the baking soda? And if I do add it, won't that cause my TA to go up even higher?

    Thanks,
    Ron
    20X40 Rectangle, 35K Gallons, SWG

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    JasonLion's Avatar
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    Re: Water balance testing

    Welcome to TFP!

    You should trust your own test results over what the pool store says. If there is any doubt, do the test again yourself. There is no point in adding baking soda unless your own test results show a number down around the one the pool store got. Pool store test results are wrong a surprisingly high fraction of the time. Also, you never want to use the stabilizer correction when deciding if your should raise TA. The "corrected" number is only used for calculating LSI (which most people can completely ignore).

    By the by, with a SWG, we recommend TA be between 60 and 80.
    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

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    Re: Water balance testing

    Thanks Jason!

    That's what I thought but wanted to make sure.

    It hasn't been easy keeping the TA level in 60-80 range. As soon as I get it there it creeps back up. It must be due to the fill water. Not having any water features to aerate doesn't help much either.

    And thanks for all the helpful advice on TFP and BBB method! It just works.

    Ron
    20X40 Rectangle, 35K Gallons, SWG

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    UnderWaterVanya's Avatar
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    Re: Water balance testing

    Measure your fill water and report back the results...

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    Inlaws Pool Boy since June 14th 2012, Pool built ~ 2003, In-Ground, 16'x32'
    13500 gal, Vinyl Liner, Fiberglass Slide, TF-100 Test Kit, Hayward 210T
    sand filter, A.O. Smith 1.5HP main pump motor (C48L2N134C1),
    Hayward SuperPump (model ?), Polaris 380 & PB4 Booster Pump

  5. Back To Top    #5

    Re: Water balance testing

    Tested the fill water.

    TA 170

    So, that is indeed the source of the increasing TA level.

    Ron
    20X40 Rectangle, 35K Gallons, SWG

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    UnderWaterVanya's Avatar
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    Re: Water balance testing

    Quote Originally Posted by TXRon
    Tested the fill water.

    TA 170

    So, that is indeed the source of the increasing TA level.

    Ron
    Yup. Lots of acid use in your future to keep the levels down. You can try using rain water as another source for fill water.

    Sent via Tapatalk...
    Inlaws Pool Boy since June 14th 2012, Pool built ~ 2003, In-Ground, 16'x32'
    13500 gal, Vinyl Liner, Fiberglass Slide, TF-100 Test Kit, Hayward 210T
    sand filter, A.O. Smith 1.5HP main pump motor (C48L2N134C1),
    Hayward SuperPump (model ?), Polaris 380 & PB4 Booster Pump

  7. Back To Top    #7

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    duraleigh's Avatar
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    Re: Water balance testing

    Just for clarification, do not plan on using just acid to lower your TA. Your pH will be driven down to unacceptable levels.

    As you likely already know, TA must be lowered using the aeration/acid process outlined in Pool School.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  8. Back To Top    #8

    Re: Water balance testing

    Per pool calculator, added enough MA to drop ph to 7.2 as well as brushed the walls/floor. Turned the returns up with pump on high to aerate and will continue to do so until ph comes back up.

    Lather, rinse, repeat.

    Ron
    20X40 Rectangle, 35K Gallons, SWG

  9. Back To Top    #9

    Re: Water balance testing

    Right now it takes around 24 hours, running the pump on high speed with returns facing up, to bring ph up from 7.2 to 7.5. I also want to add borates to the pool this spring for reasons other than keeping ph from rising as fast.

    Given:
    My fill water has high alkalinity (rising TA)
    I have a SWG (rising ph)
    I need to add MA to decrease ph to 7.2 and lower TA, then aerate at least 24 hours to raise ph back up to acceptable range

    When:
    I add borates

    Then:
    Would I expect to have to aerate longer?

    Ron
    20X40 Rectangle, 35K Gallons, SWG

  10. Back To Top    #10

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    Re: Water balance testing

    I am not so sure that you will need to aerate as much as you might think.

    I would first control the assumed rising pH with muriatic and then monitor the TA. If TA stays somewhat reasonable (say 120 or so) AND your pH does not require CONSTANT muriatic to keep it in the 7's, then there is no need to aerate.

    I don't personally use borates but I don't think that will make very much difference, if any, in your aeration process.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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