I don't close or cover or swim either (southern AZ) but my water level is not drained and I have to keep the pumps and chemistry going all winter long. My pump times go down to ~ 4 hrs/day and I can usually set my SWCG to < 20%. Testing remains roughly the same (1-2 times per week with K-2006 and daily pH/OTO testing with cheapo test kit). Brushing and vacuuming are unchanged.