I have a 30gal Long with a Fluval 304, rated at 260GPH. I have it cranked at about 3/4 power angled right at the surface on the far side of the tank aiming laterally. On the opposite side of the tank, I still get the protein film. I have a spare Rio 600 which I see is 200 GPH. If I added this pointing the opposite way in the tank, aimed at the surface, would this give me too much water movement? I positioned it and turned it on for a couple of seconds, and it looked like a cyclone in the tank. The sand was still settle, but the detritus in the bottom of the tank kind of swirled. It seemed like it would be a pain in the butt for the fish to swim/sleep in this type of current.