... (Carbon filter)Activated carbon filters used to remove the pigment in the water, smell, a large number of chemical and biological organisms ... oxidation of bad news, to restore the performance, can effectively remove a number of metal ions in water.1.3 Third stage ... used for water softening, primarily to remove hardness of water. The hardness of water is a major calcium (Ca2 +), magnesium (Mg2 +) ion ...