whats your flow like? You can feed until the cows come home but if its not suspended in the water column then its pointless.
as for lights - how often do you change your bulbs and what kind do you use.
coral - some corals are just slow growers - maybe post some pics and some of the seasoned reefers here can comment on how those corals are doing in their tanks. Some of the reefers here with amazing sps and other coral growth have commented that they have a coral or too that just grow super slow no matter what they do. Maybe get a couple frags of some stuff known to grow like weeds, throw it in your tank and see if those take off. If so you then theres nothing wrong except for your coral selection
though from the sounds of it you seem to have the ideal coral environment. Maybe recheck your p04, n03, n04 with a different kit to make sure your parameters are correct.