just speaking from 4 years of experience with this lighting (within a 7 year old tank, which was fish only for its first 3 years) i have kept softies under 2 regular out-put flourescent (1 24'' hagen powerglow and 1 24' marine glow''). My corals did fine, they are all still alive. Granted i went through some expiramentation with the lower lghting corals and polyps. Growth was very slow (except for a colt coral which eventualy recceded and died from stress due to my clown taking it as a host). I have some sort of green finger leather (not sur eif its lamnelia or sinularia or what, havnt gotten a proper I.d yet., cabbage corals, sinularia. Infact all sofites except yellow tonga leathers did fine under that lighting, agian just not very fast growth.
Your lighting will be more than sufficent if your using pc's. My tank was also deeper than yours.