Personally I would build my own using ahsupply.com kits. I have a single current satalight on a 20 high, it does well but its REALLY crappy compared to the one I built for my 55gal. But I bought the current used and cheap, so really no complaining. I would not get a double inless you want to go with presurrized CO2 as well. The moonlight does not light much of anything, its just a single LED. It could be a good fixture with some modifications though. I plan to eventually replace the square pin socket it comes with with a straight pin one. All my other fixtures use straight, but this one has to be different
. Also plan to rid out that LED and put a cold cathode in its place, then I will have a moonlight.