with a little research you will find that T5's and MH are the way to go. That way you can keep anything you want depending on wattage of corse. T5's are fairly new and becoming much more popular do to the amazing colors they can bring out in your corals and they are much better on the monthly electric bill. MH have been around a while and are very trust worthy. The also run very hot which will lead to a more expensive electric bill and the bulbs cost more.