Total calcium (Ca) percent
Total magnesium (Mg) percent
provided, that the effective date of such regulation shall be not less than six (6) months following the issuance of the regulation; and provided further, that for a period of two (2) years following the effective date of the regulation, the equivalent of calcium and magnesium may also be shown in the form of calcium oxide and magnesium oxide and/or calcium carbonate and magnesium carbonate.