PRO SERIES® Boric Acid helps create clear swimming pool water and leaves water feeling soft and soothing. To keep water feeling soft and soothing, maintain a borate residual between 30-35 ppm. Adding 1 lb of Pro Series Boric Acid into 10,000 gallons adds approximately 2 ppm. Twice a year, test pool water for borate and apply Pro Series Boric Acid to adjust if necessary.