I converted from MH/T5's to LED's for this tank. I'm rocking the Kessil a350; it's perfect for the 18" cube with really ideal spread and no bleed. I'm starting to notice that my SPS seems to be beautifully colored on the top directly under the lights but it doesn't seem to spread to the rest of the body. I'm not sure if this is a result of the angle on the LED's, a quirk of my parameters, or the fact that this fixture is set up like a spotlight.