I just got my pool last August (3 yrs old at that point), and it's a SWG pool. From day 1, the pH has been high and has been very stubborn to get into range. It was around 8.2 to start with. I used dry acid in my attempt to lower it. I slowly and steadily added alot of sodium bisulfate over a 3-week span (2 bottles -- 12 lbs), but it didn't have the affect I expected. The lowest I ever read was 7.8, but the majority of the time it would be 7.9-8.0. I struggle to have confidence in my reading of the color scale, but these are my best guesses. The sample remained some shade of purple, so I know it wasn't in the 7.4-7.6 range. I then gave up and shut down for the winter.
Fast forward to this spring. I've began using muriatic acid to try to lower it. See below for the gross details. I've added what seems like quite a bit of acid, but the pH is still very slow to move. Am I missing something, or should I just keep doing what I'm doing? I know that SWG pools tend to constantly push the pH up, and I know that I'll probably require a regular "maintenance dose" of muriatic acid to maintain pH in range. I'm just surprised that it's so hard to get it in range.
Can you guys give me a feeling of what life is like with a plaster/gunite pool with SWG, and if this is typical?
I love my new test kit btw.