Funny you should ask that. I was going to ask the same question!
I bought a 1400lph max flow powerhead for my tank. I put it on the right side of the picture, in front of the outlet pipe (hood filter) and point it lengthwise and slightly upwards to create a ripple effect. This results in a clockwise flow within the top part of the tank. Did that because not sure if all my fishes like the extra flow. It appears that the rainbowfishes does, as they are forever "surfing" in the current. My firemouth isn't too bother from what I've observed...
Adrian