SpaGuard Chlorine Concentrate (5 lb)The sanitizing power of chlorination in concentrated granules. Chlorinating Concentrate should be added directly to spa water while the pump is running. Use regular doses as a sanitizer and shock doses as an oxidizer. SpaGuard Chlorine Concentrate is a granular stabilized chlorinator, it's fast acting, quick dissolving and acts as a sanitizer and oxidizer; no need for two products. No pre dissolving needed, it can be added directly to your spa. When