As a new pool owner five years ago, I started using bleach after stumbling across this very helpful forum. However, I found I was going through a gallon of muriatic acid every week to keep the pH down. I noticed after switching to trichlor tablets (when I left the house for two weeks and had no one to watch my pool) that my pH had kept an even 7.5 since I'd left. I found that in fact my pH never varied as long as I'd use trichlor. The only problem of course is the buildup of CYA--which seems to climb almost precisely 50ppm per six months. Draining my pool every 18 months is not something I find that economical, (and seems wasteful), so after draining my pool completely last July, I used trichlor till last January (when CYA reached 50ppm) and went back to bleach. Sure enough, with an alkalinity of 70, starting at 7.2 pH, I notice my pH rises 0.2 to 0.3 four days after adding 121 fl. oz. of 8.25% bleach. So, just 363 oz later, I'm having to dump half a gallon of muriatic acid to get pH down to 7.5. Of course my alkalinity goes down slightly, so I have to dump in baking soda. Sometimes I wonder if replacing 28,000 gallons of water is more economical in the end--definitely a lot less trouble using trichlor.
The reason I bring this up is because when I've searched the forums here, I keep seeing that bleach isn't supposed to raise pH much over-all--especially with a low TA, yet that's not been my experience at all; so I'm curious if I'm doing something wrong or missing some key element? Is it ok to drive my TA much lower than 70 to help buffer the effects of bleach?
Thanks in advance for any advice...