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Thread: Lowering TA

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    Join Date
    Jul 2007
    Location
    Katy, TX.
    Posts
    37

    Lowering TA

    I am having to lower my TA for the first time in 9 years on this pool.
    My current numbers are as follows;
    FC-12 (just finished shocking a couple of days ago)
    CC-0
    TA- 120 (initial was 150)
    CH-290
    CYA~ 60-65
    pH-7.2
    Borates-45
    salt-3100
    plaster pool (21,500 gal), SWG
    I've never had to lower my TA here, I usually have to add baking soda monthly to maintain 80-90, so this is new to me. I assumed the TA would come down naturally but after a month it was not moving. It is my understading that TA comes down with lower pH values and moves up with a higher pH. So, how much below my target of TA=80 should I seek for when I raise the pH backto 7.7 or so? Is it advisable to continue circulating 24hr/day while at these low pH values and is it detrimental to the pool/equipment to hold thes low pH values for a few days while lowering TA?
    Thanks for the advice,
    Larry
    21,500 gal. IGP, Diamond Kote plaster, spa, and waterfall features, flagstone coping w/ flagstone/river pebble decking. Pentair NSFP 60 filter, 2-ea. 2 HP Whisper Flow pumps, 1-ea. 3/4 HP Hayward booster pump for Polaris 3900 cleaner, AquaLink RS6 controls, GoldLine SWG, T-15 cell

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    Re: Lowering TA

    Quote Originally Posted by Duk
    It is my understading that TA comes down with lower pH values and moves up with a higher pH. So, how much below my target of TA=80 should I seek for when I raise the pH backto 7.7 or so? Is it advisable to continue circulating 24hr/day while at these low pH values and is it detrimental to the pool/equipment to hold thes low pH values for a few days while lowering TA?
    Thanks for the advice,
    Larry
    Let the aeration of the waterfall be what raises the pH back up to 7.7 or so, then add muriatic acid to bring it back down to 7.2. That is what lowers the TA.
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

    Pool owner since Nov 2008, Trouble Free since April 2009. Happy to help when I can.

  3. Back To Top    #3

    Join Date
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    Re: Lowering TA

    Quote Originally Posted by anonapersona
    Let the aeration of the waterfall be what raises the pH back up to 7.7 or so, then add muriatic acid to bring it back down to 7.2. That is what lowers the TA.
    So, if I understand you correctly, I may need to perform this cycle multiple times. I guess you would check your TA each time you bring your pH back up to 7.7 (by aeration) or so to see where I'm at? Is it a problem to be at this lower pH for a day or so?
    Thanks,
    Larry
    21,500 gal. IGP, Diamond Kote plaster, spa, and waterfall features, flagstone coping w/ flagstone/river pebble decking. Pentair NSFP 60 filter, 2-ea. 2 HP Whisper Flow pumps, 1-ea. 3/4 HP Hayward booster pump for Polaris 3900 cleaner, AquaLink RS6 controls, GoldLine SWG, T-15 cell

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    dmanb2b's Avatar
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    Re: Lowering TA

    The addition of muratic acid lowers TA. Aeration raises PH without affecting TA. I know TA of 120 is not optimal, but are you experiencing frequent PH rise? If not, there is no rush to lower TA, especially if in the past you say your TA has naturally fallen over time. Higher TA promotes PH rise.
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

    Pool School, TFTestKits, Pool Calculator

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    Re: Lowering TA

    pH at 7.2 is not supposed to be a problem. I am lowering TA in my pool now and we swam at pH of 7.3 and my husband said it stung his eyes a bit, just a bit. TA was 140 at the start of May and is 80 now. So every few days when pH gets back up to 7.8 I drive it down to 7.2. My pH is constantly rising due to the spillover spa and waterfall. My fill water has TA of 350 and so anytime I add water I am raising the TA a lot. And twice this month I wandered off while topping off the pool so I really messed with the numbers that way. So keeping TA down and watching pH is a constant thing for me.

    So, yes, the procedure is to use MA to run pH down to 7.2 which also lowers TA, then circulate and aerate as much as possible to get the pH to raise up but TA will stay lowered. Then check what TA is before adding MA again so you don't add too much for the new values.

    Using Pool Calculator for my pool volume, at TA 120, I need 62 oz of MA to lower pH from 7.7 to 7.2, but when TA is down to 80, that same pH change takes only 43 oz of MA.
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

    Pool owner since Nov 2008, Trouble Free since April 2009. Happy to help when I can.

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    Re: Lowering TA

    Quote Originally Posted by dmanb2b
    The addition of muratic acid lowers TA. Aeration raises PH without affecting TA. I know TA of 120 is not optimal, but are you experiencing frequent PH rise? If not, there is no rush to lower TA, especially if in the past you say your TA has naturally fallen over time. Higher TA promotes PH rise.
    yes, my pH is is always rising. I use a minimum of 48 oz. of MA/wk. I have not checked my fill water this year, but it seems something has changed as the TA does not fall as it used to. I normally have to add 5-6# of baking soda per month. I'm running the water falls and circulating now to raise the pH to 7.7 or so. I will test again in the morning. It seems to take alot of MA now with the borates.
    Thanks for the help,
    Larry
    21,500 gal. IGP, Diamond Kote plaster, spa, and waterfall features, flagstone coping w/ flagstone/river pebble decking. Pentair NSFP 60 filter, 2-ea. 2 HP Whisper Flow pumps, 1-ea. 3/4 HP Hayward booster pump for Polaris 3900 cleaner, AquaLink RS6 controls, GoldLine SWG, T-15 cell

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    dmanb2b's Avatar
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    Re: Lowering TA

    Anytime Larry...yeah, borates have that effect. It will take more MA to lower PH, if you have borates at 50ppm. Since you are experiencing that much PH rise, you can target TA of 60-70. You'll get there
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

    Pool School, TFTestKits, Pool Calculator

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    Re: Lowering TA

    Quote Originally Posted by dmanb2b
    Anytime Larry...yeah, borates have that effect. It will take more MA to lower PH, if you have borates at 50ppm. Since you are experiencing that much PH rise, you can target TA of 60-70. You'll get there
    So, would that be good advice for me as well? I do not have borates but I am always dealing with the pH rise. I've never tried to get TA below 80 before. Should I try for 60?
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

    Pool owner since Nov 2008, Trouble Free since April 2009. Happy to help when I can.

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    JasonLion's Avatar
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    Re: Lowering TA

    The first thing to try is to either lower TA to 60 or let it drift down to 60 by it's self. Borates can also help, however borates is more work/money, so not the first thing to try.
    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

  10. Back To Top    #10

    Join Date
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    Re: Lowering TA

    Update; After running the water falls and circulating for approx. 8-1/2 hrs. the ph is 7.6 and TA is 100. My plan is to lower the pH at least one more time to 7.2 and aerate back to 7.6-7.7. Slow progress.
    Larry
    21,500 gal. IGP, Diamond Kote plaster, spa, and waterfall features, flagstone coping w/ flagstone/river pebble decking. Pentair NSFP 60 filter, 2-ea. 2 HP Whisper Flow pumps, 1-ea. 3/4 HP Hayward booster pump for Polaris 3900 cleaner, AquaLink RS6 controls, GoldLine SWG, T-15 cell

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