About This Item Get a visible sparkle and crystal clear water in just 24 hours! Traditional chlorine products contain cyanuric acid CYA. When too much CYA builds up it can cause overstabilization or chlorine lock cloud your water and cause algae growth. The Cal Hypo based formula in HTH Chlorine Granules Ultra provides chlorination without adding extra CYA for beautifully clear water all season. The all in 1 action also kills bacteria and algae clarifies and softens pool water prevents stain and scale and provides a filter aid for the ultimate convenience in DIY pool care. This product is great for all pool types including vinyl lined pools and salt water systems. How To Use HTH Chlorine Granules Ultra Follow the on pack dosage instructions according to the size of your pool. While the filter pump is running during the evening use a clean dry scoop to apply chlorine granules evenly over a wide area in the deepest part of the pool. Use a brush to disperse any granules that fall to the bottom of the pool. When granules have completely dissolved use HTH 6 Way Test Strips to test free available chlorine FAC residual. Do not enter your pool until the free available chlorine residual is 1 to 4 ppm. About HTH Pool Care HTH was developed with the pool owner in mind. We know that maintaining your pool water can be a lot of work. That is why we are here every step of the way helping you clear the uncertainty from pool care. With economical easy to use solutions HTH is designed to work hard so you are prepared to tackle whatever life throws in your pool. From balancing your water to treating green water we offer a full line of products to keep your pool water healthy and your swimmers happy.