I was curious as to whether the fluval 404 can provide enough surface agitation through the ripples it produces or do I need to raise it to actually churn the water. No more airstones for me.
Sponge filters never hurt anybody, and they would provide some surface agitation as well. Also, if your power goes out, you have a large bacteria colony in your tank that doesn't need power like a canister. Also, if you want to start a new tank, putting an established sponge filter is a great way to jump start a cycle.