i have a pool that i cover with a solid cover for the winter. the cover has good number of small holes so it's not water tight.
2 years ago i pumped the water from the cover to the pool before opening. i opened to a bright green transparent color. with enough bleach it went to clean in a matter of day. oh, yeah - it also had 2 dead chipmunks half dissolved in the shallow area
last year, i got rid of the water from the cover and opened to slightly green still transparent water. the same shocking process brought it back to sparkly clean.
right now after a lot of snow i have a lot of water on top. maybe a foot or so. due to tiny holes in the cover i think i will open to greenish pool and will have to shock it anyway. so i'm wondering if i should pump it back into the pool right now while the water temp is barely above freezing? or will it make no difference?