A gas injection nozzle that includes an elongated gas conduit that comprises: a first gas conduit segment configured to be coupled with a gas reservoir; a second gas conduit segment fluidly coupled to the first gas conduit segment and defining a downward curve of the elongated gas conduit; a third gas conduit segment defining an upward curve of the elongated gas conduit that extends to a sealed end and is disposed in a mirrored relationship with at least a portion of the second gas conduit; and a central gas conduit segment coupled between the second and third gas conduit segments, the central gas conduit segment having a first aperture formed in an upper surface of the central gas conduit and a second aperture, larger than the first aperture, formed in a lower surface of the central gas conduit directly across from the first aperture, wherein the elongated gas conduit has a first diameter along a portion of its length that includes at least the second, third and central gas conduit segments and wherein the central gas conduit segment includes a substantially horizontal portion that extends on each side of the first and second apertures for a distance that is at least twice the first diameter of the gas conduit.