Light saturation is generally based on water clarity and par value of the bulb...among other things (reflectors, dist from water, etc). T5's have a much higher PAR value than CF
You can have too much light for certain corals, but never too much light for others. I have 2 175w MH
and 4 NO 40w floursecents on my 75. I have a small frag of some kind a leather a local reefer gave me a few years ago. It has not grown at all, while my SPS
grow very nicely.
Which light to use is user preference. What do you want to keep? There are many people who keep SPS
coral with lots of T5's, while I don't know of anyone using CF
only and having success with SPS
. Comes down to what you want to keep.