I had the my pool builder open the pool for me yesterday. I grabbed a sample of water as soon as the cover was off. I was surprised that my TA was at 20 and that my Ph was at 7.0. When it was closed last October, the TA was around 100 and my Ph was very stable all summer around 7.8. The pool was closed with a safety cover that lets melted precipitation through. I drained water a couple of times over the winter. Perhaps 6 to 8 inches of 2 different episodes.
Obviously, I'm going to work on bring the levels back to the appropriate range, but I was just curious if this is a normal occurrence for a closed pool.