Cathodic potential oscillations were previously reported for the electrodeposition of metals. Similar oscillations are reported here for the first time using a redox couple, The previously identified rules governing the appearance of these tap oscillations plied current density larger than the limiting one, hydrogen overpotential larger than a minimum value) were either confirmed or demonstrated and expanded. Surface films, which may be linked to the reaction product solubility, are formed that limit oscillation duration. The added criteria allows a more focused search for other redox couples that may lead to unlimited oscillation durations.