Looks like a basic O2 setup to me. A diffuser that produces "micro bubbles" is what you need. Also, the Low flow regulator is the best. I have 2 sets I put together and work great.
Texas Anglers Recognition Program
TPWD Official Weigh Station
Coastal Bend Weigh Team, Cert. Weigh Master
Pro Tournament H2 Series Deluxe Scale
CT Calibration,Inc., Holden Roofing