It would really only be 108watts of day light if you're running 2n2. I would agree with IDream, I would suggest starting with some softies. I would try mushrooms I have them growing even underneath rocks on the bottom of my tank.
If you really want to keep a variety of coral I would suggest you possibly go with a 6 bulb fixture or ultimately a t5 w/ hqi mh
I'm kinda a cheapskate and a diy guy myself so I found a couple old core 250w mh
ballast on craigslist for $100 on the pair and got bulbs, reflectors and mogul sockets for $130 at the Lfs
. The core ballast are honestly about bullet proof as long as they don't get wet and you can find them used for cheap.
I switched from 4 48" vho
and and my coral growth tripled and the color of the coral to this day keeps getting better.
If you have a 75L would be better for florescent and a 75tall may result in lack of light in the lower half or third of the tank.