• Low-chlorine spa sanitizing cartridge maintains a consistent 0.5 � 1.0 ppm free chlorine level at all times
• Shock only once a month and use up to 75% less chlorine
• Floats in spa water and flips over when empty, indicating the SmartChlor cartridge needs replacing
• Lasts 3-4 weeks in spas up to 600 gallons
• Designed for use with Spa Frog @ease Mineral System