The "hard" part about
SPS is that they are very finicky about annoyingly consistant water conditions. They want rock solid temp,
alk,
ca numbers. They want flow like crazy. They want PRISTINE water conditions with no
DOC. The more you have the faster you're going to burn through
Ca &
Alk. They generally require a
Ca reactor to keep things stable and possibly the dosing of
Kalk. They don't like any temp swings. They're particular about how much light they get. They want lots of it. Wild colonies have a MUCH harder time acclimating to tank conditions. There's a good chance that a wild colony will brown out. Much more so than a
frag.
They are also more prone to parasites that can wipe out your entire tankful. Redbugs will cause your corals to stop PE, growth and color. To treat them requires the use of interceptor which will kill all of your inverts. There are also monti-eating-nudibranches that will eat all the flesh off of your corals. I would strongly suggest that you do prevetitive treatements of Interceptor, FWE and ReefDip before any corals make it into your main system. You'd be well served to
QT ALL corals before they enter your system... colonies and
frags alike. You'll catch the stuff there that could otherwise wipe out your entire
SPS collection. With a system as large as yours you want to do more prevention. Especially on a new/wild caught colony. Something small that comes in out of the ocean can be devistation to your closed environment. You don't want to have to do your learning curve on a tank that size so do your homework!!
Other than that they're not hard at all!