In - line system is built right into the spa and uses the same mineral and bromine cartridges as the Spa Frog Floating System. For easy top loading or replacement cartridges, simply open the cap, pull up the holder and snap them in. Cartridge allows you to safely drop your bromine level to 1-2 ppm and lasts up to 4 months.

Benefits:

• Conditions the water for a softer feel
• Helps maintain a neutral pH
• Polishes the water for clarity
• Lasts 4 months