Okay experienced TFP pool operators... My DH and I need some help.
We live in SE Michigan and have a full sun all day pool. We have a clear bubble cover that is on whenever we are not swimming, though there is a lot of swimming and frequent "high bather load" situations. Our current CYA is 55 (I plan to take a reading tomorrow again to confirm), and our FC will go to zero during the day from well above the target FC. Recently went from 11 ppm to 0 in a matter of 4 hours, not in a SLAM situation.
We are currently at the end of a SLAM after FC dropping to zero... Water is and has been crystal clear, no appreciable CCs, and tonight it should hopefully pass the OCLT. Not holding my breath, but it looks promising. I have scrubbed everything including the skimmer and light niche (and we left the light out so the niche is getting SLAMed too) and we've been vacuuming a lot. During the SLAM, given no CCs, we put on the opaque winter cover to be able to hold chlorine during the day, and it is working when it is on (but we do swim daily). But we clearly have an issue with something... Not enough CYA? Need opaque regular cover? Backup anti-algae treatment? We just don't know what to do next, but it feels like the land of the neverending SLAM here. My DH is seriously considering going to the pucks in a floater to help keep FC up during the day. I am not ready to give up on TFP but right now our weekly liquid chlorine costs are way crazier than dumping water from excessive CYA when we need to shock in the future. It feels a teeny bit hopeless at the moment.
Got any advice? Any gut feelings on what might be going on here? This is our second year of pool ownership and our first year with chlorine (after successful Baqua conversion).