Abstract: In an electrolytic method for removing metal from solution, a "plating" voltage applied to the electrodes is reduced to a lower, "standby" value if the current drawn by the solution falls below a threshold value. This "standby" voltage, however, is periodically restored to its higher, "plating" value for brief intervals so that the current at the higher voltage can periodically be sampled. If it is found that the current drawn by the solution at the higher voltage is once again above the threshold value (indicating that new metal has been added to the solution), the electrode voltage is kept at the higher level until the solution is again depleted of metal to the point that the current drops below the threshold. If, during the brief sampling interval, the current is still below the threshold, the electrode voltage is returned to its lower, "standby" value and another current sample is taken at the next interval.