SpaEase Mineral Stick contains a mineral formula that destroys bacteria while neutralizing acids, which helps keep the pH in an acceptable range with less monitoring and assists in keeping your water crystal clear. Using the SpaEase mineral stick helps reduce required levels of bromine or chlorine, improves spa pleasure by reducing the problems associated with bromine or chlorine, including faded bathing suits, premature damage to spa equipment or surfaces and smelly odors. Works on spas up to 600 gallons and requires replacement every 4 months, depending upon usage. RECOMMENDED USE Simply place in the spas skimmer basket and replace every 4 months. Should be used with bromine or chlorine and follow all directions for proper use of balancing and maintaining water quality.