Hello. I tested my CYA a month ago and it was around 40. I then remeasured it this week (a month later) and it jumped to 95+. To make sure, I brought water to the pool store and they also tested it at 95+.
Is it normal for the CYA to jump so much in a month? What could be going on? All of the other readings are normal, although in the past week, the FC level dropped to nearly zero, then I shocked the pool and got the FC to rise, but then it seems to have dropped to around 2.0 again.
Prior to this I have never had an issues with keeping FC stable. I am using the cholorine tabs in the chlorinator. Also, it has been crazy hot in Connecticut (90*+) for a few weeks with no rain.
Any thoughts?? Thanks!!