SpaEase uses the highest concentrate available on the market: 99% Sodium Dichloro and 55.5% Available Chlorine. Unlike many competitors our chemicals are produced and packaged in the USA, guaranteed to be fresh. Our Chlorine contains no scale forming minerals, dissolves instantly and is specifically formulated for warm water use in hot tubs! RECOMMENDED USE With pump on, add 1 teaspoon per 200 gallons of water on initial treatment. Repeat every 15 minutes if necessary to reach a 3 to 5 ppm of available chlorine. Use test strips to maintain 3 to 5 ppm reading. After each usage of spa it is recommended to add 2 ounces of Spa Activator (per 300 gallons of water) to shock and treat the water. Spa Activator does not raise yourMaintain 3 to 5 ppm of chorine and add Spa Activator weekly even when spa is not in use.