I don't 'close' my pool in the Northeastern US sense. I add a lot of bleach, turn off the heater and run the pump about 2 hours a day all winter. The lowest the pool water temp gets is about 45 degrees. My pool (despite an automatic cover) gets a lot of pine needles and worms during the winter. Every spring I open to a mess and have to drain a lot of water because of all the undissolved solids. This year it occurred to me to leave the Polaris in the pool and go out and run it periodically to try to keep the debris in check. Can the Polaris tolerate being in cold water for 6 months? It's been a great little workhorse the past 8 years. I'd hate to kill it!