I'll let those with more experience weight in - but I will share that I recently came to the realization that it really doesn't take much surface agitation at all to ensure enough oxygen for your fishies.
Especially with a planted tank and the o2 that the plants give.
I'm slowing coming around from the "if it ain't splashing, it aint' oxygenating" way of thinking. I'm surprised at how little surface agitation is needed, actually. I've currently got my cannister output below the surface only making gentle waves, and the fish seem perfectly happy. Even small neons are way at the bottom, hanging out in low-flow areas; no signs of gasping whatsoever.