How essential are bubblers?

[ksane]

So then the general concensus is that since my filters do NOT break the surface and there is no surface agitation, I should turn them back on?

This exact question was asked on WetWebMedia.com awhile back. The answer (by Neale Monks) was that water circulation 'counts' the same as surface agitation. Take it for what it's worth. I don't use bubblers in any of my 20-some tanks but I've got powerheads in most of them. That would really help to move the water around, too.
Edit: Duh. I should've finished the thread before I posted-when will I learn? Star_Rider already answered the question and you already put the powerhead in lol

 

[jpappy789]

Never purchased one. Slappy is 100% correct, you really only need a ripple to get sufficient gas exchange.

 

[mikeb210]

I've tried to diffuse CO2 using several different varieties of airstones, and I'm not sure they actually diffuse all that well. I had problems getting the CO2 to mix into the water column, and I don't see why oxygen would be any different. The bubbles are just too large from most airstones.

 

[SubRosa]

I only use air to drive sponge filters in breeding tanks, unless the fish I'm keeping come from cool rapidly moving water. Hillstream Loaches, Darters, and fish from similar environs need all the O2 you can give them.