I'm trying to think how hard it would be to get to it to clean it off if it was surrounded by big flat rock. . I haven't bought my pond for the duck pen yet so I'm still weighing my optionsI do have a filter box in my big pond but I only have the built in pump filter in my little pond. I do have to hose it of once in a while as it does get clogged with debris but it unattaches from the pump itself easily so the pump can just stay in the water all the time.
