Keep the pool ready for use with Clorox Pool & Spa Chlorinating Tablets. They work hard to keep your water clean from both harmful bacteria and unsightly algae, saving you both time and money. Each tablet is stabilized to ensure protection from algae and bacteria. They're also protected from sunlight, enabling them to last for a longer period of time. Use these Clorox chlorine tablets weekly for a good, clean swim you, your family and your friends can enjoy. For use in your pool's skimmer, feeder or floater. These tablets are composed of 99% chlorine, making it arguably the strongest chlorine tablet on the market. Some tablets contain additives that add certain features such as killing algae, preventing corrosion and improving filtration. But if you want a strong tablet with the highest chlorine content you can find, this is it. Make sure you pair this 3in chlorine tablet with a quality shock, such as Clorox Pool&Spa Shock XtraBlue. The best time to apply these products is during your weekly testing when you balance your water.