High TA but low PH - water crystal clear

Problems relating to pH and total alkalinity.
Increase ph, increase TA. Reduce pH, reduce TA.
pH chemistry advice and techniques for the pool.
Pool Newbie
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High TA but low PH - water crystal clear

Postby mumto2boys » Thu 22 Jan, 2009 18:47

My TA was reading at 200 and my Ph at 7.8. The pool shop told me to add acid to reduce TA and this would then also bring Ph down. I added the acid last night (16 hrs ago) and ran the pump for 4 hours. This morning I have tested and the TA is only down to 180, but the Ph is down to 6.8. Should I be worried?? I am very new to maintaining a pool as we have only just installed it this year (in Australia). The water is Crystal clear at this stage and every other reading is within ideal range. I did have the solar cover on overnight, so have now taken that off and am running the pump. Does it take longer than the time I have given it for the acid to work on the TA?

chem geek
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High TA but low PH - water crystal clear

Postby chem geek » Thu 22 Jan, 2009 22:13

You may have some small error in your measurements since adding acid to a pool with a pH of 7.8 and TA of 200 would either end up at a pH of 7.17 and a TA of 180 or a pH of 6.8 and a TA of 156.

At any rate, you lower TA through a combination of acid addition AND aeration of the water. So if you aerate the water you can raise the pH with no change in TA. See the procedure in this post.

It will take multiple cycles of acid addition, aeration and further acid addition to get your TA lowered. For aeration, you can turn your returns upward, run the pump on high (if a multi or variable speed pump), use a shower or fountain, turn on waterfalls or other aeration features, etc.


High TA but low PH - water crystal clear

Postby Guest » Thu 22 Jan, 2009 22:53

Many thanks - will give the aeration a go and see what happens.

I appreciate the help! 8)

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