To me, the primary considerations are pretty simple:
1) Is there ANY chance of freezing? If yes, don't open.
2) When can you reasonably expect your water to be warm enough to swim? I use solar heating so a good patch of sunshine and we can swim in early May in N-Central NJ.
3) If it's too cold to swim, and going to be, then you'll want to delay opening as long as possible--why burn electric and chlorine if you don't have to?
4) OTOH, if you are seeing algae growth, you may want to open so you can filter and shock heavily.
Bookmarks