5 Steps to Properly Shock a Pool and Kill Algae

Shock to the correct level for your CYA Look up a cyanuric acid/chlorine chart and raise chlorine to the shock level based on your CYA reading. Guessing a generic amount rarely works.

Keep chlorine high for at least 24 hours Super-chlorinate and maintain that shock level until the water clears and combined chlorine hits zero. Walking away after one dose lets algae survive.

Brush and run the pump continuously Brush every surface you can reach while the pump runs 24/7. Vacuum to waste if possible, and backwash or clean the filter when pressure rises.

Confirm algae is dead Algae is dead when it turns white or gray and stops coming back after brushing. Do not stop treatment early.

Prevent recurrence with consistent chlorine and optional phosphate remover Keep your normal chlorine level steady going forward. If phosphates are high, consider a phosphate remover as a secondary step.