I second ScubaGuy on the "seeding" of live rock being a fair/cheap way to go. I've personally only used about 30% "live" rock when starting each of my tanks, and I'm in the planning stages of another where I'll do the same. Basically you get base rock (also called reef rock) which is basically just old, dried out rock that came from a reef somewhere. It doesn't retain the bacteria, coraline algea, or hitchhikers that live rock has (and may or may not look bleached), but if you have it in a tank next to live rock, that live rock will "seed" the base rock. Bacteria will build up in/on it, coraline algea will grow, and eventually you might not even be able to see a difference between the live rock and the base rock. It's taken about 4 months for most of the base rock in my latest tank to look like the live rock, but it certainly does look great. Anyway, it's a great money save since you'll usually spend less than half as much on base rock than you do on live rock. Hope that helps.
