I'm getting three of them 2 10k and the actinic for my 57g Illuminata. If you go to kessils sight if you havent already, they have some examples of these on a tank. I think the second spotlight down they have a 1/2 and 1/2 comparison up and you can see a huge difference in the amount of light going into the tank. Was going to wait for the 350 to come out but think the 150's will do