Hi! I’ve been doing a SLAM since Monday as we were losing chlorine fast. Been vacuuming / brushing walls/ taking a toothbrush to returns, skimmer, and light. Pool has been clear since starting SLAM. Lost 2 PPM Chlorine overnight last night, we had a ton of rain yesterday and had to empty water from the pool also we had a ridiculous amount of worms because of the rain. That was all cleaned up before checking chlorine last night. So as I said we lost 2 PPM overnight. Checked at 6 am ( CL 21) lost but didn’t have to add chlorine. Checked again at 9 am (CL 17.5), lost 3.5 PPM, added 1 gallon of 10% should’ve raised it by 7.1 should’ve raised it to somewhere around 24.6 ( I knew I wouldn’t be able to get back to it for a few hours) rechecked at 2:15 and it’s 13.5 
My CYA level is 50 so I shouldn’t be losing this much during the day. What am I doing wrong or what should I be checking. Haven’t tested anything else since Monday due to the SLAM PH was 7.2 prior to starting. In the past before I learned about TFP I could always “see” the film of the CYA on the top of the pool, not seeing that at all. I’ve rechecked the CYA twice and yes the CYA reagent Is fresh, just got new stuff yesterday. HELP. I’m struggling here!!
My CYA level is 50 so I shouldn’t be losing this much during the day. What am I doing wrong or what should I be checking. Haven’t tested anything else since Monday due to the SLAM PH was 7.2 prior to starting. In the past before I learned about TFP I could always “see” the film of the CYA on the top of the pool, not seeing that at all. I’ve rechecked the CYA twice and yes the CYA reagent Is fresh, just got new stuff yesterday. HELP. I’m struggling here!!