We achieved some good depth in our tank by first getting a tank that is 18" from front to back, then by placing the rock such that the bulk of the rock is closer to the rear, sloping toward the front and with a few pieces sitting quite low and coming quite near to the front glass. We kept some areas open - just sand, and have a big arch near the back that you can view through to the rear wall of the tank. Still waiting on Santa for the digital camera - sorry no pics. But soon
