Not sure if there'd be enough flow possibly if a power head was pointed in it's general direction? One way I always checked flow in a tank was to crush up some flake food really finely and put that into the water, it's like they do at those shows with the fluorescent balls, but it's food to eat.
Edit: Oh didn't notice the pump at the bottom, interesting way of doing things. I might put some holes in that up pipe so that the water can squirt out in multiple directions.... but test it out first.
