Finally, in the last section I wanted to make a lagoon with low(ish) terraces that hovered over the sand. One criteria here is that I did not want the appearance of a heavy base rock supporting the terraces. Instead, I used a slab of tavertine as my anchor and drilled holes into it where I would insert very long and thick rods to support my terraces. If you've never seen or worked with tavertine, it is a very very dense and heavy rock! They use it to build buildings! I would then cover up the exposed acrylic with rubble epoxied to it. The tavertine is a tan colour that perfectly matches the sand bottom.
I guess now is a good a time as any to let the cat out of the bag. Way back in the beginning I had made a decision to go bare bottom. Well, after staring into my 150 for the past few weeks and then seeing the aquascaping come together I decided that I truly am not a bare bottom kind of guy. Sure it looks cool, but I think sand looks better, more complete and natural. The decision to put some sand on the bottom helped me to put all the pieces of my puzzle together. For example, I can now hide those acrylic panels that I glued my live rock too and I can partially burry the travertine slab so that it blends in with the sand.
Anyway, here's one of the terraces drilled.
And here they are built up.
Note: When dealing with live rock you have to work quickly. What I had on hand was a tub with heated salt water from the tank that I could use to dunk the rock into every now and again to keep them moist. Unfortunately this made for a very messy rock building session.