I'm going to have 2 course pads, a medium pad, and half a tray full of filter floss. I am just going to use the media in 1/2 of one of the trays, just so I have different types of stuff for the bacteria to grow on. I see your point in the "just mechanical" part though. I never thought about it like that. But I think I will add some sort of bio media, just not sure what type and what the differences each type has.
We don't inherit this world from our parents, we borrow it from our children.