Clarifies Cloudy Water. SeaKlear Natural Clarifier got its name because it was originally used by the U.S. Navy to clear seawater for underwater photography. Environmentally safe, nontoxic and biodegradable, SeaKlear Natural Clarifier contains a natural ingredient, chitosan, which attracts the organic debris that causes cloudiness in pool, spa and hot tub water. A floc or mass of organic material is formed and carried to the filter, where it is more easily removed. Easy-to-use, SeaKlear Natural Clarifier is an excellent clarifier. Each week, treat your water with SeaKlear Natural Clarifier specially formulated for pools or spas/hot tubs to improve water quality and clarity. With SeaKlear Natural Clarifier for Spas, use 1 ounce per 500 gallons of water, and with SeaKlear Natural Clarifier for Pools, use 1 ounce per 5,000 gallons of water