New guy, Rock and sand questions

[Der_Iron_Chef]

Welcome!

Are you definitely wanting a sand substrate, or have you considered the possibility of a barebottom tank? Different looks, pros and cons for each, etc.

As far as live rock....I never considered what "type" of rock I was getting when I bought mine. As long as it was live rock, I was pleased! I personally don't think it matters what type. Some people have preferences, and maybe they can/will chime in. If you're creative with your aquascaping, you can make for an attractive setting.

My advice regarding a clean-up crew is: if you want some crabs, get only one or two. I find that they eventually kill each other off (just my experience talking here), and/or they knock things over. They can also kill snails as they grow larger. I would just focus on having some effective cleaners like snails, and perhaps a cool-looking shrimp for kicks (coral-banded, peppermint, fire, etc.)