New Lights

#1
Ok so I have a question...

I just upgraded my 55 Gal tank to a 150 gal tank, and I was using compact lights on the 55 and now have 3 150watt halides. I know this is a big change to the corals and fish (well so I think it would be) so I'm just running my lights about 5-6 hours a day. The question I have is; it seems that most of my corals have got smaller and are not as vibrant as they once were, is there something I'm doing wrong or something I should be doing different??

I transferred everything over and am running the tank the same way I was before, but with more extra's (in the helpful sense). I also have the lights about 6-8 inch's about the water line. Not sure how high they really need to be?

Any help or thoughts would be great, thank you.