Sodium chloride is the typical type of salt used in water softener systems. Sea salt is a close match. Potassium chloride can be good salt alternatives when salt isn’t available. Sodium chloride is the typical type of salt used in water softener systems. Sea salt is a close match. Potassium chloride can be good salt alternatives when salt isn’t available. Sodium chloride is the typical type of salt used in water softener systems. Sea salt is a close match. Potassium chloride can be good salt alternatives when salt isn’t available.