I used 50/50 caribsea on my 120 build. The only uglies I got were on the caribsea. If you break is open its solid. I would use it again.
Cant tell it from live rock anymore.
Thanks. No, the overflow is an external overflow. What you see there are clear plastic panels that I fastened to the back wall after gluing rock rubble to it using thick-viscosity cyanoacrylate to make a rock wall-type look. Tank was originally FOWLR, but I converted to mixed reef a few years ago. I really like the look and I have some ideas for mushrooms and polyps when I do my 300 build. Plenty of ideas, not enough cash. Lol.