AquaChek Salt Titrators measure salt (sodium chloride) levels from 400 to 7,000 ppm using a small water sample and takes just minutes. Maintaining appropriate salt levels helps ensure salt generators will be able to produce the correct amount of chlorine to keep water clean and free of contaminants. The most economical way to buy AquaChek Salt test strips in this 40 count package. For a clean and healthy pool, test the water at each end a minimum of twice a week!