I have a non-SWG pool, about 22K gallons, which uses liquid Cl.
I've never been able to figure out why my pH rises so much -- about 0.2 per day -- but I add muriatic acid a couple times a week to push it back down. I generally let it rise to 7.8-ish and then knock it back down to 7.2. The rise has gotten a bit worse recently since I stopped using pucks (which are acidic) and started using only liquid Cl. I'm wondering how much of a problem it is that all the acid additions are dropping my TA. It's about 50 right now, but I believe it will continue to drop. I tried raising it with baking soda, but as predicted, it just dropped down again over time. Just how low would be "too low" for the TA? Based on my reading, a lot of people would already say it's too low, but it won't stay higher without a constantly adding baking soda. What is the lower limit below which I should not let my pH drop?
I also read that with a low enough TA, CO2 outgassing shouldn't happen as much. Is this true? If so, how low of a TA would indicate that the pH rise is NOT due to outgassing?
I have not tried borates yet. I'm considering this, but I'm not yet clear that this will substantially effect the pH rise, and I'd rather not use borates if possible since I have a dog.
My numbers as of this writing:
FC - 7.5
CC - negligible
pH - 7.6
TA - 50
CH - 825
CYA - 60
Salt - 1800