Sanitizers are the key ingredients of proper pool maintenance. Chlorine and bromine keep the water clear, protected from bacteria and help control algae. They are part of the BioGuard 3-Step Pool Care System. Patented, easy-to-use, multi-functional granular sanitizer and shock. Excellent alternative to calcium-hypochorite products. Broadcast use (white plaster pools only) or skimmer use. Can be used with the 3-Step BioGuard Care System.