Robelle 1404 3-Inch Chlorine Jumbo Tabs For Swimming Pools, 4 Pounds 3-Inch Tablets Individually Wrapped For Easy and Safe Handling Stabilized To Protect Against Harmful UV Rays 7-Day Slow-Dissolving Tablets 90% Available Chlorine Weekly Maintenance Dosage Is 1 - 3 Tablets Per 10000 Gallons