There are many great LED fixtures for coral growth out there. It is a simple matter of physics as to the PAR output and the spectrum. In many ways they are the simplest lights we have ever seen in the hobby...they are just different. Much superior to any florescent or ballasted fixture I have ever used in my 25 years of reef keeping. I have posted about this many times before with links to inexpensive, coral capable LED arrays. One note of caution, the good ones are so bright, begin with them hung twice as high as you would hang the equivalent metal halide to avoid coral bleaching. Look for fixtures that have either 1watt LEDs or 2watt, mixed blue and white. Even more sophisticated mixtures can also be supplied. 150 1watt LEDs equals a +400 watt halide.