Working on lowering TA - question regarding 'happy PH'

[DanielJ]

New pool owner. I just recently made my final payment to the pool builder.

Here are my test results from this morning:

FC = 5.5
CC < 0.5
PH = 7.8
TA = 170
CH = 150 (based on previous test results)
CYA = 50 (assumed based on previous result of 40 and then I added 2lbs a few days ago)

I have been mildly working on bring down the TA by adding muriatic acid. I've been adding 3 cups of acid every few days. I don't usually test right after adding because I usually test first and then add acid. When I test again in a couple of days, I almost always have a PH of 7.8. I am aerating through use of SWG, returns pointed toward the surface and I have aerators installed in the return jets on the stairs. TA has not dropped measurably - I've been adding acid a couple of times a week. Is the PH always 7.8 because it rapidly returns to that PH due to the aeration? Should I expect the PH to continue to rise? It seems to get to 7.8 and stay there. I don't think that this is a big deal, but I'm curious because the recommended method for dropping the TA doesn't really seem to be working.

How often do people add acid while in the process. I suppose that I need to be more aggressive with the acid addition and sampling. Correct.

I also want to raise up the CYA some more, but I need to get to the store for more stabilizer.

 

[JohnT]

Adding 3 cups of acid would only lower your pH to a little over 7.5. The recommended method has you drop your pH down to about 7 and then aerate. It might take more than a gallon of muriatic acid to lower your pool to the area where you can get TA reduction. Unless you get your pH down in the 7-7.2 area, you aren't going to lower your TA because at higher pH there is very little carbon dioxide in the water to get rid of through aeration.

 

[DanielJ]

Thanks for the explanation!