Renew Spa Shock is a granular non-chlorine shock treatment that dissolves quickly and works instantly . with only minutes of spa downtime! This pool and hot tub shock eliminates materials which cause odors . skin . and eye irritation. Some of these spa particles include residual soaps . deodorants . natural oils and materials that can build up in spa water. Renew Spa Shock uses bromine to get rid of these microorganisms left behind by bathers. This treatment is part of the Reserve & Renew Chlorine-Free Sanitizing System. Your spa will be safe to use . again . just minutes after application. This granular shock oxidizer is compatible with chlorine . bromine . and mineral purification systems. Keep your pool or spa looking crystal clear with the Leisure Time Renew Spa Shock Chemicals pack.