Have you tried rotating the flow cages and playing around with how deep from the waterline the pump sits (I'm assuming you have it horizontally mounted)? When I originally had set mine up, I got a lot of movement on the water surface but didn't seem to be too much flow across to the other side of the tank (60" tank). I started messing with the flow cage rotations making slight rotation adjustments cause for mine I noticed that just a slight rotation made a big difference on the flow direction. I also messed with the height and found the sweet spot and find that I have to turn it down quite a bit from before or else things start getting crazy in the tank. I have it set at 50% currently.