HASA HI-TEMP SPA OXIDIZER brings sparkle to dull water caused by the buildup of organic waste in the spa water. This organic waste combines with your sanitizer in the spa water to form combined chlorine (chloramines) or combined bromine (bromamines) which can be very irritating. Shocking the spa water will ‘burn off’ (oxidize) the organic waste and nitrogen compounds to allow your sanitizer to be very effective once again.