I always lower my water level 6 inches below return,all lines disconnected and everything stored in garage.
Return plugged and skimmer face closed with cover .With winter rain, and usually somewhere between 35 and 60 inches of snow throughout winter on average, the water level by spring will be mid to upper level of skimmer.
When I used a cover for 3 years,it was sized for my pool, and had the metal ratchet and cable.
The cover would always sit on top of water which is what you want,otherwise you will stress the side walls.I never had luck with those pillows.
If for some reason you develop a leak,even small the water level will drop and the cover will drop with it and start to pull on the top rails where cable is and possibly collapsing the walls.
But this wont happen until the water thaws,wont leak if frozen.
I found this out when returning home from Vegas in early spring.
Fortunately I caught it in time when noticing the cable looked too taught around pool and cover looked like a trampoline.
And after removing snow around the house,the last thing I wanted to do is remove snow from a pool.
I only get occasional leaves/pine needles from a couple trees from neighbors house's after a very windy day, so no more cover for me , winterize, remove leaves and forget.
If you have large trees, I would probably cover,that could be a mess left open.Without cover, you close later and open sooner.Always a cold job that way around here. late March / end Oct.
