My pool is mostly shaded and was taking a while to warm up so I bought a solar cover (clear/opaque) everything was fine for 3 weeks before we were swimming (in the 72 degree water) and pool has actually been up and running for about 6 weeks. Running just like normal FC loss of about a gallon and a half of bleach a week and CYA at 40. Skip forward a bit and I put the solar cover on, first time I test after 3 days or so I notice and abnormal FC loss down to 1 ppm. I figure it must just be concentrating the UV and eating up FC. No problem I add some bleach and things seem normal. The pool heats up fast and is in the 82 degree range and seems perfect except some yellow algae has formed. vacuum to waste backflush the filter and all is fine. Now the cover has been on for 3 more days since last "normal readings" (my CH is a little low 150 but they were out at first and I have been forgetting to grab it). Today it is super cloudy and FC and CYA have dropped to zero. Added 4 bottles of bleach 3 hours ago and still zero FC.
Do I just keep adding bleach to kill whatever this is? Will it even work with zero CYA? Is my CYA really zero?
Also it has been 98 degrees here for the last three days and the pool is now 87
PH: 7.5 (maybe slightly oranger 7.6)