The SPA FROG Mineral Cartridge contains a patented mineral formula that destroys bacteria while neutralizing acids, which helps keep the pH in a safe range with less monitoring. Using FROG minerals with reduced levels of bromine or chlorine improves spa pleasure by reducing the irritations associated with bromine or chlorine including red stinging eyes, dry itchy skin, faded bathing suits, premature damage to spa equipment or surfaces and smelly odors. This product must never be used alone but always supplemented with a source of bromine or chlorine. Replace the SPA FROG Mineral Cartridge after 4 months or when draining and refilling spa with fresh water. The SPA FROG Mineral Cartridge reduces bromine use up to 50% * and improves water quality by: * Destroying bacteria for improved clarity * Helping to maintain a neutral pH * Reducing chlorine use for softer water * Compared to the minimum EPA recommended bromine level of 1.0 ppm for a stabilized spa.