I use one over my 12g nano. Works well enough. haven't used it over SPS yet though, but I only have to run it at 25% to keep my lps chalice, favia, fungia, torch, etc) happy and colorful. I'm doing two more over my larger system which I expect to have to run 50%-100% then. I like them and the dimming feature on both white and blue is a nice feature to get it to the color you want. To me, they are the same as running T5's, but less heat and energy.