the tank is 30" or 31" in height. I wanted to keep a variety of corals. SPS, LPS. The LED light is an attractive option for me I think because I am actually going through a snails pace at setting this baby up. It has sand so far and live rock will be added over the next year. I really dont plan on any corals for quite a long time, maybe a year. (grad school and being a teacher are putting a limit on how fast I move along with this project). I am hoping the price for LED lighting goes down in the future. I think you're right about the MH fixture... not worth the risk at this point. It looks like hell too.