SpaGuard Spa-Shock Oxidizer eliminates soluble organic undesirable compounds and irritants in the spa water and is buffered to prevent pH bounce. Regular use helps maintain clear spa water. This product is not a sanitizer or algicide. To sanitize your spa or for removal of algae, use the appropriate product specifically formulated for these purposes. Compatible with the spas using chlorinating or brominating products as a sanitizer. It does not replace the need for regular application of chlorinating or brominating products.