The anode of an electroplating apparatus is incorporated in a sparging plenum. The plenum has an insulating partition separating the anodically biased electrode from the workpieces being plated. The partition has a regular array of orifices. Electrolyte is pumped into the plenum and flows out of the partition, providing a spacially uniform supply of fresh solution to the workpieces. In a soluble anode process, the solution is replenished in the plenum. In an exemplary apparatus, one major surface of the plenum is a titanium tray, which holds pieces of nickel, which dissolve during the nickel plating process.