AG Freeze Damage

[Poconos]

Hi again,
I use a gizmo to plug the skimmer pipe, then I pack pieces of eccofpam into the skimmer itself. Eccofoam is the closed cell foam that pool noodles are made from. Unlike styrofoam which shreds. Theoretically the gizmo should take care of expansion but I add the additional foam as insurance. I cut a rectangular block of the foam, probably 3" thick, that fits snugly in the opening. It's not an attempt to keep water out but rather to kind of make the pool wall continuous around the skimmer area so if the ice block moves a little there is no force at the skimmer. It extends past the skimmer face maybe an inch.
Just a quick calculation, for your 21' pool, if the ice is 12" thick, that's about an 18000 pound block of ice. Concentrate part of that in one area and you have a scrunch.
Al
BTW: Yes...I'm in the far northeast corner of the state, maybe 20 miles northeast of Scranton. Been pretty cold here too.