The aquarium is a 15 gallon Fluval Flex (with the in-tank filter behind the rear wall). I have a canister filter that I can adjust the flow to whatever rate I need, which offers me a much easier cleaning schedule as well as a few other pluses. Outflow back to the tank would be distributed with a spray bar.
I'm thinking that the water inside the aquarium's filter on the output side may become problematic, since it won't be cycling much if at all.
Has anyone nodded their Flex like this, or have suggestions other than cutting a giant hole in the black plastic?