Calgon is a brand registered trademark of different corporations. The original product consisted of powdered sodium hexametaphosphate , which in water would complex with ambient calcium ion and certain other cations, preventing formation of unwanted salts and interference by those cations with the actions of soap or other detergents. Its name was a portmanteau derived from the phrase "calcium gone". Originally promoted for general use in bathing and cleaning, it gave rise to derivative products which have diverged from the original composition. Today, Calgon water softener contains the active ingredients zeolite and polycarboxylate, which are less problematic in wastewater treatment than phosphates. read more