Aquarium Filter - Air Powered

This project IS functional and actually in my aquarium right now! (see pic above)

I've been unsatisfied with my current aquarium filter and wanted a new one of my own design, however instead of an external filter that hangs off the side of the tank I wanted to make an old-school submerged filter that uses an air pump that I can stick in the corner and surround by the river rocks I use for decoration.

This piece is designed so that it can be printed on a 100x100x100mm build surface so anyo