How did you set the pump up? the way pictured on the right seems to be the favorite way for most

that mode you get more "punch" out of them.

With a long tank like that maybe put the pump on the end opposite from your return line and try and get the flow to meet your return line flow.. when they collide it should create some turbulence. that's a pretty large tank for just one
power head tho.. you might need two to get the flow you're after.. not sure tho.. just thinking out loud.
edit: heh.. wiskey got to it before me.
