I saw a setup like the one your drawing depicts. Basically, a variation on the toilet tank setup.
The 'sump aquarium' is a separate chamber from the sump reservoir and is filtered with sponge filters.
Since the sump chambers are in back of the aquarium chamber, all of the mess is separate from the aquarium and the aquarium's water level is not dependant on the sump level.
The 'sump aquarium' is a separate chamber from the sump reservoir and is filtered with sponge filters.
Since the sump chambers are in back of the aquarium chamber, all of the mess is separate from the aquarium and the aquarium's water level is not dependant on the sump level.