Bottom portion of new base rock structure. This rock is shaped like a foot from the ankle down with the toes half buried in the sand toward the front of the tank. Powerhead hidden from view behind the rock directs flow between two mated surfaces.
Additional holey rock at bottom portion of new base rock structure. Rock pillar behind and ankle/foot shaped rock to left of this picture. Flow between rocks from powerhead directed between mated vertical faces. Vertical crevasse width is from 1/4 to 3/4 inches apart 12-15" tall and 4-6"