Hi folks - my first post, so have mercy. Found this site a few weeks back after a couple trips to pool store gave no results when I found I could not keep any free chlorine in the pool this year (6th year). Like most of you, after seeing the amazing info on this site, I am a believer.
Situation: Using newly purchased TF-100 test kit, I discovered my CyA is high (85-95), and I had more CCs than desired. I have acquired lots of bleach and been adding this to the pool (almost) per SLAM process for the last couple of weeks. I say almost because I have not raised the FC level to the full shock level ( which would be ~ 35ppm at my CyA level). At most, I've been to 8ppm. I also have not brushed (vinyl) pool walls as they appear clean to the eye, and are not slimy to the touch. Bottom line - pool water seems to be in very good condition.
Results: Pool water is super clear. I have minimal (< 0.5 ppm) CCs. However, I lose about 2ppm of FC each night, so I'm not passing the OCLT test. I can maintain this condition by adding 1 gallon of bleach every other day or so.
Questions: Why do I lose the 2ppm overnight? How often/how much bleach should I expect to add on a regular basis to maintain proper FC level in my 22,000 gal vinyl pool?
Thanks for any help you can provide!