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Thread: Lowering TA

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    Lowering TA

    I read throughout this forum that lowering the pH and aerating should lower the TA. My TA has been over 240, since I started the pool two weeks ago.

    I thought I read, but I can't find it now, that the higher TA can cause the pH to creep up. Since I am experiencing pH going up (7.3 moves to 7.8 over 3-4 days), I thought maybe this was the cause. My setup 18' round vinyl metal frame pool, 6,600 gallons.

    So if I move my pH down to 7.0, is it still OK for swimming?

    In any event, I read what seemed to me to be a nice way to aerate on this forum. I'm going to make a bubble maker out of some PVC and a valve on the end of an air hose run by my compressor.


    Kevin
    Yes, I have a pool.

  2. Back To Top    #2
    reducing TA by aeration will increase pH. Keep aerating and watch the pH doesn't get too high and it will come down. It may take a while though. Keep the pH ~7.2
    15,500 gal, inground gunite pool with 7 ft spa, 2 speed pump 2hp/.33hp, 3/4 hp booster pump, Intermatic P1353 timer, AutoPilot SC-48, Sand filter with ZeoBest, Heater, that I never use . . .

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    JasonLion's Avatar
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    A PH of 7.0 is tolerable for swimming, though it will usually cause some eye irritation. 7.2 to 7.8 is the generally recommended range for swimming.
    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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    MikeInTN's Avatar
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    You can read the stickie on how to do lower TA, but basically you add muriatic acid to lower your pH to 7.2 or so, then start aerating your water to outgas CO2. As you outgas, the pH will start rising. add more acid to lower the pH back down, and keep aerating. Keep repeating the process until your TA is at the level you want.

    I went through this process, and lowered my TA from around 160 down to around 100. I then found that my pH was wanting to bottom out around 7.2 or 7.0; I slowly started adding baking soda to raise my pH and TA until my pH started staying steady around 7.5 - 7.6. My TA is now around 120-130, and my pH stays fairly constant.
    24' x 52" AGP - approx 13,500 gallons
    Pentair Optiflo 1 hp/2sp pump w/ Swimpro Voyager 150 sq ft cartridge filter
    Intex 8110 SWCG
    "Fear the Schnauz!"

  5. Back To Top    #5
    Quote Originally Posted by MikeInTN
    I went through this process, and lowered my TA from around 160 down to around 100. I then found that my pH was wanting to bottom out around 7.2 or 7.0; I slowly started adding baking soda to raise my pH and TA until my pH started staying steady around 7.5 - 7.6. My TA is now around 120-130, and my pH stays fairly constant.
    My softened well water tests around 240 TA from the tap in the kitchen. I used this water to fill about 1/4 of the pool. I am planning to lower the TA in the pool, which is around 170, using the prescribed methods on this and other forums ( lower ph, aerate, repeat )

    Now for the questions:
    How many hours did it take to lower the TA by aerating ? I would just be using the 'eyeball' jet directed at the surface.
    How often do I retest TA during the process ?

    thanks ,

    bim
    8000 gallon, AG, Sand filter 22", 2spd pump (2hp)
    SolarPRO XD1 Solar Heater, Hayward aqua bug vac.

  6. Back To Top    #6
    MikeInTN's Avatar
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    Quote Originally Posted by bim
    Quote Originally Posted by MikeInTN
    I went through this process, and lowered my TA from around 160 down to around 100. I then found that my pH was wanting to bottom out around 7.2 or 7.0; I slowly started adding baking soda to raise my pH and TA until my pH started staying steady around 7.5 - 7.6. My TA is now around 120-130, and my pH stays fairly constant.
    My softened well water tests around 240 TA from the tap in the kitchen. I used this water to fill about 1/4 of the pool. I am planning to lower the TA in the pool, which is around 170, using the prescribed methods on this and other forums ( lower ph, aerate, repeat )

    Now for the questions:
    How many hours did it take to lower the TA by aerating ? I would just be using the 'eyeball' jet directed at the surface.
    How often do I retest TA during the process ?

    thanks ,

    bim
    It took several days for my pool. The time it takes to outgas the CO2 is dependent on how much aeration you have. The more aeration, the more quickly the pool outgasses the CO2, and the more quickly your pH rises so you can repeat the process again. I used the same method that you're going to (eyeball jet directed at the surface). I tested my TA after the first muriatic acid/aeration cycle to see how much it dropped, so I could get a fairly good idea of how many cycles I was going to need to get to my desired TA level. I halved the number of cycles, tested at the halfway point, and then tested again when I had what I thought was one cycle left.
    24' x 52" AGP - approx 13,500 gallons
    Pentair Optiflo 1 hp/2sp pump w/ Swimpro Voyager 150 sq ft cartridge filter
    Intex 8110 SWCG
    "Fear the Schnauz!"

  7. Back To Top    #7
    I just thought I'd give an update to my TA lowering.

    I haven't had time to make the aerator I talked about earlier. So I just decided to lower the pH a bunch and let the wind do some work.

    I took the pH down to 7.1, on Wednesday, and today's reading (Sunday) was 7.6. The TA had been 240, and today's reading was 200. I didn't check the TA the days in between, so it was quite a surprise. I dumped in more Muratic Acid tonight to bring it down again, so we'll see what happens next.

    And I wanted to give a big THANK YOU for all the people who help other people here.

    On an off topic subject, last weekend I experienced for the first time in this new pool chlorine smell and eye irritation, and some skin dryness. From the reading I had done here, I figured it was CC. I had also read that to fix it, you add chlorine. That night I added a bunch of bleach, to take the FC to 8. The next day (didn't get around to measuring until afternoon), the FC was back down to 5 and no chlorine smell!. The day after that we did more swimming and had none of the problems of before. Keeping this pool working right is really alot easier than I thought it would be. BBB -- its just too easy.

    Kevin
    Yes, I have a pool.

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