Solar pool covers work by allowing the sun’s heat to pass through the cover thus trapping the heat in the pool.

If the air temperature drops at night, cover the pool to retain the heat that has built up during the day.

Among the benefits of covering the pool

1. keeps it warmer at night, 
2. increases the temperature during the day,
3. reduces water loss through evaporation, and the resulting chemical imbalances,
4. keeps the pool cleaner by stopping leaves and dust from blowing into the pool.