I was just brainstorming and I have an idea that could either be good or terrible. I was thinking it could be useful to put some sort of filter pad on top of the exposed water matrix block (Aquablock) to act as a pre filter. Of course, that would look bad and would need to be disguised with something. A bunch of rocks would be a pain in the butt to deal with. What if a person used sheets of the pebbles used as "tile" in bathrooms? Mounted on mesh. I don't know if the mesh or the glue would be fish safe. Or permanent over time. But I can envision it. Instead of a bag of big rocks over the aqua block, cut a piece of matala pad or other filter media (ideally not blue or anything bright.) Then cover with sheets of pebble tile. When it came time to clean, you just remove the pebble sheets, then the pad and hose it off -- like in a skimmer. Then replace it all. It probably wouldn't work. But if Greg Wittstock made it, I'd probably buy it!