Includes the chemicals you need to close your pool, protect your pool this winter and yield the most stress-free spring opening you've ever had. The Summer and Winter Multi-Purpose Algaecide will prevent algae growth during the winter months. The Winter Stain and Scale Control will prevent stain and scale while the pool is closed. Oxidizing Shock and Swim is the highest strength non-chlorine oxidizing pool shock, effective at eliminating organic contaminants.