Hello everyone I'm introducing myself. I found this website in late August of 2019, after a nightmarish first year. I have learned a lot including testing on my own with TF-100. My CYA level was over 100 last year and the pool store assured me that it was ok up to 150. I was using those darn Trichlor sticks and it wasn't until I did my own research that I figured out pool stores just want to sell you stuff. Anyways this year the water is crystal clear, I only use liquid chlorine this year, my cya is 40, my pool only gets 4-5 hours of sunlight a day, and I use MA occasionally to bring down the PH. I'm really happy and glad I found this website, I was about to permanently close the pool without you.