I'm setting up a 50 gallon "lowboy" frag tank. Dimensions are 48" long x 24" wide x 10" high. I want to set this up as a "look down" tank for tridacnid clams & corals that are best looked at from above. So, I'd like a pump that circulates the water without disturbing the surface too much. A gyre probably fits that bill, but I hear they're a lot of maintenance. I'm leaning towards the smaller Tunze Wavebox, but those need a few inches of air at the top of the tank, and this tank is very shallow to begin with. Any other ideas?