Step 5. Shock the pool
Shock your pool on a weekly basis to destroy waste products that can’t be filtered, such as rainwater and sunscreen. Start by checking the water’s pH level and balancing it with chemicals if needed. Next, mix and dissolve granular shock with water in a pail. For your safety, always add granular shock to water—not vice versa. After adding shock to the pool, wait 1 hour for non-chlorine shock and 12 hours for chlorine shock before swimming.