I did something similar with a some pvc pipe and hose barbs, and a 100 gph pump. The problem is going to be the pump is way to small. Your probably only going to get a trickle of water out of it. I had my pump in the tank though, so I was pumping to the filter and then back up, so I had alot more head pressure. Also if I remember correctly the max those little pumps can pump is 4' high, and then it pretty much stops pumping. If I were you I would try scrubby pads instead of gravel. Hope this helps.