HTH™ Chlorinating Tabs are a simple, convenient way to keep your pool water clean and clear. Simply place tab(s) into the skimmer basket, floater or feeder to sanitize and protect your pool water from algae and bacteria. They are sun protected and designed to dissolve slowly, giving your pool a steady source of available chlorine for up to one week. HTH™ Chlorinating Tabs are great for all pool types, including small pools, pop-up and above-ground pools, vinyl-lined pools as well as salt water systems. Follow the on-pack instructions to place tab(s) in your swimming pool feeder, floater or skimmer. The amount of tabs you use depends on your pool size. Do not add tabs directly to the pool as this can cause damage to pool surfaces. Repeat every week or as often as needed to maintain a chlorine residual of 1-4 ppm.