PB_Smith
Aquarium Advice Addict
Never had one. Even in a goldfish tank with a high bioload ?
Sure. The only reason why undergravel filters can be an issue is due to poor housekeeping.
Using a gravel vac so remove muck and every couple months siphoning water from under the plate will keep it clean and working indefinitely.
but if memory serves we also had a canister filter on the 40 gallon who kept fancy goldfish in simply because they poop so much.