i was wondering, would a bubble wall (or air stone) help prevent algae since as the bubble hit the surface it causes a gas exchange, which should dissipate the C02, and thus limit the growth of algae. so, would this work?
Co2 has nothing to do with algae growth, it's phosphates and high nitrates that are your biggest concern. Too much iron can also pose a problem.
Bubble walls are pointless IMO, powerfilters provide enough surface agitation to provide oxygen and if you have live plants the bubble wall will not be helpful at all because as you said the agitation releases CO2.
It can also provide more tropical fish with too much oxygen.