Simultaneous determination of total, non-carbonate and carbonate water hardnesses by direct potentiometry.

Total, non-carbonate and carbonate water hardness have been determined simultaneously by manual and automated direct potentiometry, using the bivalent ion-selective electrode, and known addition-known dilution technique. The automated and programmable system produces direct print-out of total, non-carbonate and carbonate water hardnesses. The optimum sampling rate is 20 samples per hour. This time-saving method compares well with the standard method.