well it depends on the size of tank. i have a 29 gal with easy stuff= mushrooms, kenya tree and xenia and i have 2 white 10k 17w t8 bulbs on it. i wouldn't say its ideal, but it is a start. the corals are also in the top 1/2 of the tank.
most here will say my lighting is too low, but its working. also if you are running underpowered lighting, do not use actinic or blue bulbs. the blue is more for us than the coral. the 10k white bulbs will have more usable light for the corals
t5 fixtures really are what you should be looking at though. more power, more efficient, more bulb options, etc
ask some of your local reefers for some free easy stuff to get you going.
better to have a frag of kenya tree die than an expensive store bought coral.
happy reefing