Frog Spa Mineral Cartridge provides spa and hot tub owners utilizing the Spa Frog System with an easy way to introduce water softening minerals into their systems in a handy self-contained replaceable cartridge, eliminating the need for time-consuming chemical additives. Mineral Cartridge softens water as well as making it easy on your skin and eyes to provide a bathing environment that chlorine-based systems cannot match. This product is designed for use with Spa Frog floating or inline systems, making the task of spa maintenance much simpler.