[Steverino]

Most of the rocks sat on the horizontal tubes themselves, which are pretty much resting on the bottom glass. I had enough sand to cover most of the tubing. I used the larger pieces or rock at the bottom of course. I drilled some of the rock pieces at the end instead of at the middle, so they would create overhangs and create good coral ledges. McMaster Carr sells the arcylic rods, I believe they come in 1/8" increments, so you can get 1/2", 5/8", 3/4", 7/8" etc. You pick them up over in elmhurst at McM-Carr. The nice thing about this method is that you can slide the rocks off since they aren't glued, you can slide a piece off if you want to frag off or glue a coral to it, change out pieces, etc. The whole thing is very stable since the base structure is connected. i was afraid of rocks falling off a tall pile into the glass, that is why I did this structure.

JRAquatics, your tank looks great. I should say that gluing pieces would be fine if the tank is shallow like Jr's, but my tank was about 30" or 31" tall, so I needed some major league stacking height and having 50 lbs or rock glued together was impractical.