You are all very helpful and I am starting to get it now. I shouldn't have used the SLAM term in this case. I just re-read the chlorinating section in Pool School. I may have inadvertently caused the CYA problem - when, at the beginning of this thread, I noted the very low FCl level, I panicked and threw in 5 lbs of granular shock. My FCl rose to 5, but that's when I noticed the higher CYA level too. I did not remember there's CYA in granular chlorine. I use the Taylor K2006 test kit and I extrapolated the CYA to about 120 since the high on the tube is 100.
So, what to do now. As I was thinking of, I will not install an in-line puck chlorinator to supplement the SWG. I will use liquid chlorine to supplement. Unfortunately, during the hot summer, my SWG can't keep up even if if I run it at 100% 12 hours a day, it scales very badly requiring cleaning every 3 weeks. I'm sure the cell will burn out at this rate. We have very hard water supply here and calcium hardness is impossible to battle. pH and TAlk are optimized at 7.6 and 80.
Any other recommendations to:
- increase chlorination another way, other than adding liquid chlorine once or twice a week?
- reading about chlorine sources, thoughts about bleach vs the 12.5% chlorinating liquid?
- looks like the liquid chlorinator a will raise the salt levels. Significant in my salt pool?
- any way to bring that CYA level down without draining (very expensive water here).
Thanks,
Russ