The Cation Exchange Capacity (CEC) of the Na-form of synthesized samples of zeolite A has been studied by GLP 22 multimeter Ca ion selective electrode. For this test, 0.5 g zeolite A is first dried at 110 C for 1 h. Then it was cool down to room temperature in a desiccators, precisely weighed again and poured into a beaker containing 500 ml of 0.005 M CaCl2$6H2O. The removal of Ca2þ ion from the solution was measured with initial water hardness of 500 mg CaCO3/L, being this value considered as very hard water. The mixture obtained is vigorously agitated under room temperature for 15 min as it is considered a practical time for the zeolite exchange to have come very near its equilibrium limit. The zeolite is then filtered off and the residual Ca2þ concentration is measured in the filtrate using Ca ion selective electrode.