The theoretical calcium binding capacity of zeolite A is 352 mg CaCO3/g anhydrous zeolite A. Owing to the presence of other competing ions like sodium or potassium, in the practical detergent washing scenario, this level of calcium can not be achieved and thus calcium binding capacities of 160mg CaCO3/ g is considered as appropriate for detergent application [25]. In this study, the calcium removal capacity is expressed in mg CaCO3 per gram of anhydrous zeolite A from the solution having hardness of 500 mg CaCO3.