I really suggest that you consider getting a couple of books on saltwater to get a good understanding of things like lighting, coral types, water parameters, etc.
The questions you're asking don't lead me to believe you have enough understanding of how it works to be able to make decisions about the living creatures you want to put in a tank.
Even more so than in freshwater, you can't just put water and salt in a tank and hope that fish and corals will survive.