Abstract: A pair of tubular air-sparging elements is provided cooperatively associated with a cathode, each of said tubular elements being disposed at opposite faces of the cathode at the bottom of said cathode and running the entire length of said bottom, each of the air-sparging elements comprising an inner tube disposed within an outer foraminous sleeve of larger diameter, said inner tube having a plurality of air emitting orifices disposed along the length thereof, such that air passing through said inner tube as coarse bubbles emerges as fine bubbles through the foraminous sleeve to form a uniform curtain of air bubbles along the plating faces of said cathode which inhibits the formation of rough surface deposits.