how many hours a day for metal halides?

[burgerchow]

Hey everyone, my new tank is now up and running. 120 aqueon RR with dual overflows, oceanic 3 sump, quiet one 4000 pump, vertex in180 skimmer, coralife 2x250w aqualight pro. cheato in sump for phospates and nitrates, plus 140 lbs of the best live rock I've ever seen. ( thanks to Naesco for shutting down his tank). I've got the lights on timers. Moonlights are on 24/7, actinics are timed to come on an hour before the mh and stay on an hour after the mh go off. Question is how many hours a day should I keep the mh on? I've got some lps near the bottom and mid level, and some sps near the top. Currently have it set to come on @ 3:00 pm and off at 10:00 pm. Is 7 hours of maximum daylight enough? This is my first go with MH lighting. In the past, have used VHO , but I love the glitter effects of the MH

Thanks for any info.