I recommend getting a book and reading up on them. Corals require more care....lots better lighting...and great water quality.
I have a 55 gallon with around 14 different types of coral. I only had like 250 watts of light...then switched to 2 250 Metal Halide lights with 2 110 watt actinic lights. The difference is amazing. My acropora corals are growing like mad and my softies are twice the size! I am not saying you have to have MH's though I really recommend it.
I am just saying do your research online or even here... There are tons of places to research the care of a "reef tank"
Hope this helps.