Here is a quick one I whipped up using Modular LED.
The one thing that annoyed me was the blinding light you get out of the side when not using optics (this is limited when using U channel). The aluminium U channel is from Princess Auto and cost $36 for an 8 ft length. I run this fanless at about 110F (well within the limits).
This is over a 72x30x24 tank, with no other lighting on (crappy cell phone pic). Raising the lighting about 8" off the water limits the light separation you see in the picture.
And this is it supplementing my other DIY LED light.
