With my first tank, I made the mistake of building a rock wall against the back glass. I had all kinds of issues, and no sandbed space. The rock work in this tank is completely open on all sides. I don't think I'll ever build a tank where the rock touches the glass again. If I could offer advice to new reefers, that would be the biggest point I could stress. And I was also borderline about putting the yellow tang in this tank, but the open rock work made me feel better about it.