Directions: One (1) pound of UV Shield will increase pool water cyanuric acid level by 12 ppm. Ideal levels of UV Shield (cyanuric acid) are between 30 -50 ppm. If you sanitize with stabilized chlorine tablets such as Tri-chlor, or stabilized chlorine granular such as Di-chlor, you should keep in mind that these products contain cyanuric acid will cause your level to rise throughout the season. If you these sanitizers, you should balance your UV Shield (cyanuric acid) level to 30 ppm at the start of the season. If you use non-stabilized chlorine as your primary sanitizer, such as calcium hypochlorite, liquid chlorine or salt water chlorination, than balance your pool water UV Shield (cyanuric acid) level to 50ppm. Cyanuric acid products are slow to dissolve which is why we recommend placing your dosage into nylon stockings which can be hung into the pool near the return fittings. Applying your dosage this way prevents clogging pipes and ensure all product makes it into the pool water as opposed to sitting on the pool bottom and/or being cleaned out of your filter. Other dosage application options are on the package.