An apparatus and method for supporting a substantial center portion of a gas distribution plate is disclosed. At least one support member is capable of engaging and disengaging the diffuser with a mating connection without prohibiting flow of a gas or gases through the diffuser and is designed to provide vertical suspension to a diffuser that is supported at its perimeter, or capable of supporting the diffuser without a perimeter support. In one aspect, the at least one support member is a portion of a gas delivery conduit and in another embodiment is a plurality of support members separated from the gas delivery conduit. The at least one support member is capable of translating vertical lift, or vertical compression to a center area of the diffuser. A method and apparatus for controlling gas flow from the gas delivery conduit to the gas distribution plate is also disclosed.