Your currently rock setup looks nice, the pillar was just a suggestion. My brother did it in his 90, and it turned out pretty good. You might not want the height of a pillar on a 45, but you could use the acrylic bar to help stabilize any stacked rock. This is what I plan to do once I get another tank to make at least one pillar.
i'm going to just epoxy the stacked stuff together. Those shelf pieces at 7" tall at their highest point. I want to leave the top half of the tank open for fish to swim in and coral to grow. I thought about some pillars that come to the water line or higher but I will need to smash some of my rock up to make something that fits in. I'll give it a shot once i get some epoxy.
