You can either cover your pool or leave it uncovered, if leaves aren't a problem and there's not a danger of kids/animals falling into it. My IG stays open all year, and it stays uncovered. I leave my pump running at night when it's below freezing, but otherwise cut my pump run time to 2-3 hours per day. You keep the water in balance just like during the summer, but you'll find that as the water temp drops, so will the chlorine consumption, so your bleach additions are drastically reduced while the water is cold.

Janet