Here in Iowa,all I have done is wait till the temp of water stays at 60 or below, once I leave the heater off for the season.Usually mid to end of October .Raise FC level to SLAM level in accordance to my CYA level.I then add 60 algeacide, 16 oz for my pool.Let it circulate for a day,lower water with the pump set on waste to below skimmer, before pumps starts to suck air.
Remove more water to 6 inches below return fitting with another pump( not a sump pump), I use a small gas powered transfer pump with a hose into pool.
Disconnect everything inc. the sand filter and store in garage.I have had an issue where I drained the filter and left drain open and covered and the next spring had a leak in the seam of tank.Maybe overkill now, but sand is easily removed.Disconnect all lines to pool, vacuum water out of heater and cover.Plug return and plug front face of skimmer with plate, and this year put a 16 oz. bottle with 8 oz. RV antifreeze dropped into skimmer.Last year even with skimmer face blocked off" they aren't water proof" skimmer had a chance to get a block of ice in it, even with bottom connector open to the ground.Not going to chance it again.No trees, so I don't cover the pool anymore, too much work getting the snow build up off every time it snows.Next season usually all the levels of pool water are at near zero for me. But when you open early enough, before water gets above 60 deg. again and balance the chemicals, all should be fine.I have never had Algae issues.