Well, this thread has piqued my interest once again...and I have a few questions for you "sole" sponge guys. I am considering a switch over to solely sponges as I'm getting tired of expensive filtration units (not that I don't like them) in an effort to cut down costs, but still have highly effective filtration. I currently have a heavily stocked 72g malawi tank and a heavily stocked 55g tanganyika tank. Now say I was to go with just sponges on both tanks via air powered pumps (I've been looking at the Azoo ones that have battery backup that automatically switches on when power goes out) would flow be sufficient enough to satisfy my Malawi guys? I'm not real concerned about flow with my tang tank as they don't really care for much either way. My current maintenance schedule is both tanks get 75% water changes once a week so I don't think I would have quality problems. Also, how well would oxygenation go with just running said sponges on just an air pump vs say a spraybar from a canister etc? Reason being is I worry about surface scum building up as it is pretty unsightly.
Currently, my 72g malawi tank runs an AC110 paired with an Eheim 2075 also with 2 Koralia 750's...so you can see my concern with overall flow throughout the tank vs just sponges.
Any insight to my food for thought? Sorry for a long winded post.