SpaGuard Rapid-Dissolve Shock Oxidizing TabsSpaGuard Rapid Dissolve Shock Oxidizing Tabs will effectively eliminate non living organic waste and contaminants in spa water. This product is buffered to prevent pH bounce, so it will not affect your pH level. Using the Oxidizing Tabs regularly will help maintain clear spa water, and prevent future problems. Non chlorine shock oxidizer Quickly oxidizes non living waste and contaminants One bottle treats average sized spas for 12 weeks