I had several goals in mind when I set out to design my dream tank. First, and most obviously, it would be large, both for the increased room for inhabitants, and for the added stability of a large volume of water (the solution to polution being dilution). I never liked, however, the look of a wide, short tank. My tank would be tall: a 40 inch column of water with dramatic vertical aquascaping (and a 72" × 30" footprint). Knowing from experience how easily an acrylic tank can be scratched, and no longer having to design for earthquake resistance (farewell, southern California!), I chose to have a glass tank built.
As our home doesn't have any location that lends itself to an in-wall tank, the filtration would have to be contained in the stand, and the tank would be viewable from three sides. Therefore, I needed an overflow that would fit within the tank (rather than hanging off the back of the tank, and preventing it from being pushed flush with a wall), and that would not reduce the visibility from the side panels, while still accommodating a great deal of surface skimming and allowing me to hide as much of the display tank's plumbing as possible. The solution was a full-height, extra-wide trapezoidal overflow with room to conceal all three of the 1.5" drain lines, as well as the two 1.5" sump return lines and the 1.5" intake for the closed-loop system, and which wouldn't interfere with the view from the side panels. To accommodate all of that plumbing in such a small space, the floor of the tank could not be glass. So a PVC-bottom tank with low-iron glass viewing panels was what I eventually ordered.
In addition to the six 1.5" bulkheads in the floor of the overflow section, there are six more 1.0" bulkeads in the floor of the display section of the tank, to accommodate the six outputs from the water distributor in the closed loop system. Four of these are evenly spaced along the front wall of the tank, and an additional two are near the back of the tank, by the corners of the trapezoidal overflow.