Quote Originally Posted by SunnyOptimism View Post
Hi @Watermom!!

I just wanted to say that I have seen this warning a lot (in various context, not just from you) and I have to say that TriChlor pucks have never had any substantial effect on my pH. Now my pool water normally likes to rise in pH, I have an SWCG and a gunite pool so all those factors probably contribute to trichlor' lack of effect on my pH. Also, trichlor tabs take forever to dissolve in a float for me (typically 10-14 days for three 3" tablets to fully dissolve) so while the water locally around the float might be low pH, my pool water pH barely moves.

Truth be told, I rarely use pucks (only when my CYA needs to be bumped up) so I'm not regularly exposing my pool to trichlor.

Just thought I'd share my thoughts on the subject....
You have other factors acting to raise pH. Many people have a constant rising pH with SWCGs (I don't--don't know why). Many people also have rising pH while their masonry pool is curing. So all your tri-chlor was doing was offsetting some of the upward pressure on pH.

I went away once for 2 weeks (9 or 10 years ago) and left 4 floaters full of Trichlor tabs. When I came back, my CYA went from 30 to 70, my FC was about 5 or 6, but my pH had dropped below the measurable bottom of 6.8. 4 boxes of Borax later I was back in the 7's. At the time, here, there wasn't much discussion of the acidity of Tri-chlor tabs, merely of the additional stabilizer. So I asked the question and the answer came back: Tri-chlor is highly acidic.