a product including potassium monopersulfate and a halogen is presented . the product is useful for treatment of aquatic facilities such as swimming pools . while it was known that using a combination of potassium monopersulfate and halogen is effective for sanitizing water , a product that includes both components could not be made because of the incompatibility between the two components . the product overcomes the incompatibility by use of a barrier film between the two components . the barrier film , which includes one or more of inorganic salt , silicate , borosilicate , and organic polymer , is coated onto one of the components prior to being combined with the second component . the product may be extruded and molded into a desired shape and added to the water to be treated , as needed .