Potassium alum is the common alum of commerce, although soda alum, ferric alum, and ammonium alum are manuf for purification of drinking water and industrial process water.
Potassium alum is the common alum of commerce, although soda alum, ferric alum, and ammonium alum are manufactured. Alum has been used at least since Roman times for purification of drinking water and industrial process water.