This Winter Closing Kit contains everything you need to close your pool this fall. Designed to treat pools up to 25,000 gallons. This kit will condition the pool water and prevent algae growth throughout freezing winter months to ensure a sparkling clean pool. It is designed to care for your pool over the winter months when your pump and filter are not running to help ensure a trouble-free Spring opening. It is safe for use with chlorinated pools, saltwater pools, and pools using Pool Frog systems.