arianna06,
First and far most Welcome aboard,
2nd stlouisguy is trying to offer you one of the best pieces of advise that one can give to some one just starting out in this Hobby.
We are all here to help and give free advice. We have watched way to many new people come and go in this hobby because they moved way to fast, and could not keep things alive. I'm not say you don't know much about saltwater, but I can remember when I first started, and thought I knew enough about what I was doing to start adding lots of corals.. I was wrong and almost gave up till someone pointed me to RC.
Still to this day I research every Coral, and every Fish I put in the tank prior to buying it. Some corals will introduce unwanted pest in the aquarium whether it's on the coral or the Rock it is attached too, and there are only certain ways of getting them out. IE Nudi's, Redbugs, Flatworms, Aiptasia, Majano. All of these can take over the tank very quickly. Plus every type of coral requires different type of Lighting, flow, and Placement. Some corals will kill other corals, and cannot be placed next to each other, and other corals do fine next to each other.
Again welcome to RC and SLASH and I hope to see you around more. If you have any questions feel free to ask a way. We are all here to help.
There will be a Frag swap on the 27th of this month at Noon. You should come and check it out.