3-pack of FROG SmartChlor replacement Cartridges for use with the FROG @ease Floating Sanitizing System Mineral Cartridge, Cyanuric Acid free, ideal for hot tubs up to 600 gallons | SmartChlor is a patented chlorine formula that adds a low level of chlorine only when needed for continuous crystal clear water and peace of mind; it works with FROG Sanitizing Minerals. | FROG @ease uses SmartChlor, a patented chlorine formula that adds a low level of chlorine only when needed and combines with FROG Sanitizing Minerals, creating Fresh Mineral Water for continuous crystal clear water and peace of mind. | You use up to 75% less chlorine* with FROG @ease, making water easier on skin, hair, swimsuits, and your hot tub’s surfaces. Condition the water for softness, absorb acid to help keep pH balanced. | With FROG @ease, you shock only once a month, or when draining and refilling your hot tub - that’s so much easier than shocking after every use - it saves time and the frustration of constant shock treatments