As for my opinion on TBS, it is great if you want to add diversity to your tank, and wish to have excess of 1.5 lbs/gallon in your tank. The rock is extremely dense which is why you need so much of it. Must of the base rock placed into the ocean to aquaculture is mined from phosphate pits and the like, which is not what I want in my tank. It is also mostly encrusted with sponge and tunicate life with excellent coralline coverage. I can grow coralline, and sponges and tunicates have very mixed results upon curing, and depending of aftercare. Beyond this, the level of undesirable hitchickers ( the aformentioned "diversity") gave me endless headaches with my gulf/keys rock in my first reef tank. Coral eating lympets, zoanthid spiders/nudis, GORILLA CRABS (so many it needed capitalization), mantis/pistol shrimp, bad stars, fantastic odor (lol), and algae blooms (bad bad bryopsis). None made it into my new tank. Although I spent additional money on new rock. My previous delight with haitian rock has left me jaded now though. The tiny encrusting tube worms that came from it, and now cover my back glass, eat so much calcium and strontium, corraline has taken a back seat. Walt smith premium fiji is fine rock so long as you get it from a reputable source. There are better but rarer sources as well. The tonga Kaelini is really pleasing me with it's arrays of coralline colours, as well as shape. As is the indonesian, but this tends to be somewhere between Fiji and Gulf in density, so you will pay more for it, and need more of it. I just set up a 20H zoa tank with only 2 pieces of Indo. a 13lb and a 12lb piece. Covered in coralline of the deepest purple tone, with some nice pinks splotched about, with a healthy covering of a Gracilaria like macro algae, and some chaeto looking stuff as well. So far no spike, at 13 days.
P.S. Mike, sorry 'bout the hijack.