a conductivity measurement system provides one or more dc pulses to first and second electrodes submerged in an aqueous solution such as , for instance , the wash water of an industrial dishwasher . the voltage at the first electrode is measured at a sequence of at least three predetermined times after initiation of one of the dc pulse . a non - linear curve fitting function is applied to the sequence of at least three voltage measurements to calculate the voltage at the first electrode at the beginning of the dc pulse , commonly denoted as being at time t = 0 . the resulting calculated voltage at time t = 0 is then used to calculate the conductivity of the solution , and / or to control operation of the a chemical dispenser , and / or to perform another predetermined system analysis or system control function . in addition , the difference between two of the measured voltages , such as the first and second measured voltages , is compared to a predetermined threshold value to determine whether the electrodes are so contaminated that polarization compensation is no longer feasible , thereby signaling that the electrodes should be cleaned or replaced .