Clorox Pool&Spa XtraBlue 3 Inch Chlorinating Tablets go the extra mile to help maintain healthy pool water. These multi-functional pool chlorine tablets work hard to keep your water clear from both harmful bacteria and unsightly algae. Each tablet dissolves slow and contains stabilizer for a long lasting clean. The XtraBlue Formula protects your surfaces from scale and corrosion. And with conditioners added that make your water feel silky smooth, you'll want to jump your clear pool every day. Maintaining 1-4 ppm* of Free Chlorine is critical to keeping water clean and suitable for swimming. Use weekly in skimmers, feeders or floaters. Always apply chemicals per label directions. Circulating pool water when applying chemicals helps disperse chemicals throughout the pool for maximum coverage.The best time to apply these pool tablets is when you test your water each week with the Clorox Pool app. Since it gives a personalized recommendation for what your pool needs, there's no guesswork involved. Simply enter your test results or scan a Multi-Use Smart Strip. Then apply these chlorine tabs as recommended, along with any other Clorox Pool&Spa chemicals recommended such as balancers or Shock XtraBlue.