This SeaKlear spa balanced shock oxidizer contains a high level of active oxygen and minimizes pH fluctuation. It oxidizes with active oxygen instead of chlorine, so use of the spa can resume just 15 minutes after treatment. Use weekly to keep water clean, clear and free of musty and chemical odors. Works quickly - resume use after just 15 minutes. Removes odors and chlorine smell. Uses active oxygen, not chlorine. Eliminates organic contaminants, suntan oils, and perspiration. Made in the united states. Use 2-ounce of SeaKlear spa balanced shock oxidizer for up to 500-gallon of water in spas and hot tubs weekly. Available in 2-pound.