i plan on keeping soft and hard corals, as well as an anenome. the manager of my LFS said even a 150 watt would probably overheat my little tank. he was also trying to tell me that metal halide bulbs need to be replaced as often as power compact? i get the feeling he was just trying to sell me power compact lighting because he doesn't have any metal halides for sale. i'll be building the canopy for a metal halide retrofit. do i need a fan?