Do air pumps really provide oxygen into the water?

[tcarswell]

I am surprised nobody has mentioned sponge filters yet. Do the sponge filters that are air pump driven actually serve a dual purpose and help oxygenate as well as provide a large surface for the growth of Benneficial Bacteria?

I may be over oxygenating all of my tanks. I run top HOB filters (Mainly AC70's and AC110's) to disturb the surface in parallel with an air pump driven sponge filter and at least one airstone in every tank that I have!

Im curious as I do the same thing. I have an AC110 as well as plenty of other surface agitation. BUT I also have the large 50 dollar Penn Plax dual outlet. Both of them power small sponges that way in case of a power outage I have some very minor backup filtration.

One more question

I hear that the nitrification process requires oxygen so canisters that dont break the surface or create adequate exchange can actually deprive oxygen ? This is just what I read in a few freshwater books. Any experienced folks on the matter have input ?