Well, when I tried my old Betta in a 10 gallon with a HOB filter, it got pushed around quite a bit. I even tried 2 different kinds of HOBs.
I originally wanted to use an airstone in that tank to help reduce the water temp. But, since I installed the air conditioner in the room, I no longer have to worry about that.
I also went out and bought some 1" airstones this weekend. So if I ever get the urge to put an airstone in that tank again, I'll have a stone better suited for that tank.