That's interesting, and very uncomplicated compared to what I'm trying to do.
In my latest incarnation of a sump filter,
I actually use some scrubbies as my pre-filter and diverter, down thru a floss filter, and thendown thru a scrubbie trickle filter, a layer of lava, then up thru a gravel bed followed by heater then past 2 big air powered Bacto-surge sponge filters.
When I change the floss, I fold it up and squeeze some of the juice into the trickle tower, then I toss it.
Finally I set up a flower box full of ivy and some return water trickles through the roots of this before it goes into the tank.
This is all very new and I don't have a clue how it's going to work. The only part of that system that is aged right now is the sponge filters.