Quote Originally Posted by boscogabby
Very helpful thread. I have an Aquarite SWCG and I have a PH of 7.4 and TA of 120 which I am able to maintain pretty consistently without adding acid. However I am reading alot in this thread about adding acid to maintain PH. Is this because most of these pools are plaster and not vinyl? I have an inground 12,000 gallon vinyl pool. Filter runs 12hrs a day and SWCG at 20%.
Quote Originally Posted by boscogabby
The only chemicals that I add are ph+ (sodium carbonate) and ph-(dry acid) from pool store. This is my first season with SWCG, used to use Baquaglop. I have not yet had an upset through a heavy bather load and I really do not do anything but vacuum after bad weather conditions, I just let the extra water evaporate. My latest test results are 5ppm FC - PH 7.4 - TA 120 - CYA between 60-70 and Calcium hardness at 250.
I see from your two posts above that you use ph+ and pH-. This tells me that you are using up salt for the process, and will eventually have to add some when the low salt alarm comes on. Dry acid is acid but in a different form, as it dissolves to form sodium sulphate and sulphuric acid. No problem in that but it tends to skew your argument regarding not having to add acid.

The total dissolved solids will increase in the pool accordingly, and may well be assisting the TA in acting as an extra buffer to minimize pH bounce. This is just a theory on my part. Someone with better chemistry than I, hopefully may enlighten us further.

Pat