I have a 120 gallon tank that's 48 x 24 x 24. I want to do a mix of mostly sps and some lps, and softies. I want to know what are some of the cheapest light fixtures/combination of light fixtures that I can use for this tank. I would like to keep it under $500. I really like metal halides but am not liking the cost it would be to run them. Any suggestions?