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.