[Chemical name] sodium hexametaphosphate [Chemical formula] (NaPO3)6 [Common or alternative name] Sodium polymetaphosphate, Calgon water softener [Source and description] 
This water softener, surfactant and detergent is the primary ingredient in Calgon water softener. It is available at the grocery and hardware store. It is also known by other names including: glassy sodium, Graham's Salt, and hexasodium salt.