Air or no air?

[p3rf3ctsp3cim3n]

I was under theimpression that it was the water agitaion at the surface that made the O2 exchange into the water..........

Exactly what works for me. My outflow is at the top of the surface and it creates a strong current. Beneath it I run a small 10gal flow pump with air line hooked beneath it creating automatic bubbles. As they rise to the surface it is strongly pushed around. My tank is pretty good aerated b/c of it. On the negative side, you do get a bit more evaporation though.