Low TA High PH

[txwillie]

PH is around 8.0, TA is around 80. From past experience, I think that if I can get the TA up to 120-140 the PH will stabilize. in the 7.6 range. I recall a post sometime back about a proceedure where you would shut everything off and let the water get totally dead calm and then dump a good dose of baking soda in the middle and let it sit for 30 minutes or so. This would raise the TA without affecting PH much. Can anyone help me out with this?

txwillie

[anne]

I may be wrong, but I dont think that having the water calm vs agitated will make a bit of difference. pH is going to change if you add any thing acidic (H+) or basic (HCO-). So adding sodium bicarb has to have some effect on pH, but since it itself has a pH of 8.3 (thanks, Doc) it cannot change your pH by more than 0.3.

When I have been in that situation, I add baking soda as needed to get the TA in a good range, and then a bit of acid (or if it is time to shock, it is a convenient time for MPS) to drop the pH. I know that others handle it differently, but I can't keep a happy tub if the TA is only 80.

[Tman122]

PH is around 8.0, TA is around 80. From past experience, I think that if I can get the TA up to 120-140 the PH will stabilize. in the 7.6 range. I recall a post sometime back about a proceedure where you would shut everything off and let the water get totally dead calm and then dump a good dose of baking soda in the middle and let it sit for 30 minutes or so. This would raise the TA without affecting PH much. Can anyone help me out with this?

txwillie

To be honest I think I would leave that alone and see where it goes, depending on your sanitizer it may come right to you in a couple weeks or so. If the TA does drop a bit you will get a better response from Baking soda if the tub is dead calm and left to sit, I have seen it. But your PH may still climb just a bit.

[Reese]

I may be wrong, but I dont think that having the water calm vs agitated will make a bit of difference. pH is going to change if you add any thing acidic (H+) or basic (HCO-)...  

I'm with Anne.  I've seen advice suggesting that calm vs. pumps running, broadcast vs. column application, and pre-diluted vs. direct application all may create different effects on pH or alkalinity, but I've never seen any scientific explanation of why.  Unless an application method results in a different reaction or more/less off-gassing that affects the acid/base balance, it seems to me that a given amount of acidic or basic material should affect pH the same regardless of how it is applied.  :-?

[txwillie]

I may be wrong, but I dont think that having the water calm vs agitated will make a bit of difference. pH is going to change if you add any thing acidic (H+) or basic (HCO-). So adding sodium bicarb has to have some effect on pH, but since it itself has a pH of 8.3 (thanks, Doc) it cannot change your pH by more than 0.3.

When I have been in that situation, I add baking soda as needed to get the TA in a good range, and then a bit of acid (or if it is time to shock, it is a convenient time for MPS) to drop the pH. I know that others handle it differently, but I can't keep a happy tub if the TA is only 80.

Totally agree with Anne. Added 2-3 oz of baking soda at noon yesterday. Tested around 7 and did not notice any change in either TA or PH. Raining again today, so probably won't check again until tomorrow. As for the calm water thing, it is just something I read on here 1.5 - 2 years back. When I used that method B4, it seemed to raise the TA but not the PH. Might do just the same thing if the pumps are running.

txwillie