Embodiments related to increasing a uniformity of an electroplated film are disclosed. For example, one disclosed embodiment provides an electroplating apparatus comprising a plating chamber, a work piece holder, a cathode contact configured to electrically contact a work piece, and an anode contact configured to electrically contact an anode disposed in the plating chamber. A diffusing barrier is disposed between the cathode contact and the anode contact to provide a uniform electrolyte flow to the work piece, and electrolyte delivery and return paths are provided for delivering electrolyte to and away from the plating chamber. Additionally, a vented electrolyte manifold is disposed in the electrolyte delivery path immediately upstream of the plating chamber, the vented electrolyte manifold comprising one or more electrolyte delivery openings that open to the plating chamber and one or more vents that open to a location other than the plating chamber.