Well there a couple ways of light acclimating. One is to place new arrivals low in the tank and slowly move them up to where you want them. Another way, which is also useful when replacing old lamps or changing K
's, is the screen acclimation. Basically put 2-3 layers of screen, maybe more depending on what your tank/new coral is used to, over the top of the tank. Remove one layer every 7-14 days to slowly introduce the corals to the higher intensity lighting.
As far as heat goes, I don't think w/ just one MH
it will be too much of an issue.