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Thread: Lower TA by muriatic acid followed by borax?

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    Lower TA by muriatic acid followed by borax?

    My borax level is low, and my TA is high. A thought occurred to me: can I lower TA faster by lowering pH with muriatic acid, wait for a few hours, then add borax to increase pH, then repeat? Aeration seems to take a long time to raise pH.
    15k gunite pool. Intelliflo VF. Autopilot SWG.
    2k separate spa with waterfall (ie: pain in the rear maintaining a separate body of water). 2HP Hayward Tristar pump.

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    Richard320's Avatar
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    Re: Lower TA by muriatic acid followed by borax?

    Why are you worried about high TA? Does the pH jump a lot? Are you dangerously close to scaling? It will come down eventually if you just maintain the pH. Every pool has its own personality. Some will have a pH flatline at 100 TA, some will battle the pH until TA is 60. If it's not causing any problems, why mess with it?
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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    Re: Lower TA by muriatic acid followed by borax?

    From what I understand, lowering the pH with MA will lower the TA, raising the pH with borax or baking soda will also raise the TA. So you end up back where you started.

    The only way to raise the pH without raising the TA is aeration. It just takes a little time and patience. I dropped mine from 240 to 65 by repeatedly adding MA to drop pH to about 7.0, then aerating to bring it back to 7.5. In a few days I had actually overshot my goal. It works you just have to be diligent and patient.
    chiefwej
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    Re: Lower TA by muriatic acid followed by borax?

    From what I understand, lowering the pH with MA will lower the TA, raising the pH with borax or baking soda will also raise the TA.
    Pretty close, but not quite. I always remember them like this......

    Lower pH - use muriatic....TA also comes down
    Raise pH - use borax.....it has little effect on TA

    Lower TA - acid and aeration method....see Pool School
    Raise TA - use baking soda....it has little affect on pH
    Dave S.
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    Re: Lower TA by muriatic acid followed by borax?

    Quote Originally Posted by duraleigh
    Lower pH - use muriatic....TA also comes down
    Raise pH - use borax.....it has little effect on TA
    Borax raises TA by half as much as pH Up, but it still raises it. In fact, borax raises TA by slightly more than Muriatic Acid lowers it, assuming you end up at the same pH (though the extra amount of TA that borax adds is borate ion, not carbonates). Borax is a base and any base raises both pH and TA. Lye (sodium hydroxide) would also raise both the pH and TA. So it is inaccurate to think that borax has little effect on TA. The see-saw most absolutely happens if you add Muriatic Acid and then add borax. You cannot lower TA that way at all. You have to outgas carbon dioxide and aeration at low pH speeds that up.

    A better way of looking at this is that all acids lower pH and TA while all bases raise pH and TA. pH Up (sodium carbonate) is a combination product that is identical to a pure base (lye; sodium hydroxide) with baking soda (sodium bicarbonate) so ends up raising TA about twice as much as a pure base so roughly twice as much as borax.
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    Re: Lower TA by muriatic acid followed by borax?

    Quote Originally Posted by chem geek
    Borax raises TA by half as much as pH Up, but it still raises it. In fact, borax raises TA by slightly more than Muriatic Acid lowers it, assuming you end up at the same pH (though the extra amount of TA that borax adds is borate ion, not carbonates). Borax is a base and any base raises both pH and TA. Lye (sodium hydroxide) would also raise both the pH and TA. So it is inaccurate to think that borax has little effect on TA. The see-saw most absolutely happens if you add Muriatic Acid and then add borax. You cannot lower TA that way at all. You have to outgas carbon dioxide and aeration at low pH speeds that up.

    A better way of looking at this is that all acids lower pH and TA while all bases raise pH and TA. pH Up (sodium carbonate) is a combination product that is identical to a pure base (lye; sodium hydroxide) with baking soda (sodium bicarbonate) so ends up raising TA about twice as much as a pure base so roughly twice as much as borax.
    Thanks chem geek, as usual, you come through!


    Quote Originally Posted by Richard320
    Why are you worried about high TA? Does the pH jump a lot? Are you dangerously close to scaling? It will come down eventually if you just maintain the pH. Every pool has its own personality. Some will have a pH flatline at 100 TA, some will battle the pH until TA is 60. If it's not causing any problems, why mess with it?
    Richard, a high TA causes my pH to go up quickly, and I do already have some scaling at the water line. Unfortunately, I battle high pH even when TA is at 60, probably because of the high aeration I get due to spa jets running in the spa. Even if I lower pump time to half an hour.
    15k gunite pool. Intelliflo VF. Autopilot SWG.
    2k separate spa with waterfall (ie: pain in the rear maintaining a separate body of water). 2HP Hayward Tristar pump.

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