I tried one and decided I didn't like what t5 did for the light in my tank. I tried several different t5 bulbs and was still not happy. And I'd be happy to sell the 36" Sun Blaster fixture and 3 t5 bulbs (plus an led bulb made for the fluorescent fixture!). I only used it for about 4 weeks!
I ended up getting 2 led strip fixtures. I added an all blue strip with a dimmer at the very back edge of the tank (just inside the eurobrace) and a half white and half blue strip with 2 channels and 2 dimmers at the front edge of the tank.
I was MUCH happier. With dimmers you can control how bright the additional light is. The t5 light just wiped out and overpowered the main led fixture. Also, with the white and blue strip in front, I could adjust for how warm or cool I wanted the additional light to be without buying multiple new t5 bulbs! This also accomplished 2 other goals. First, the front led reduced the shadows from the primary led fixture almost, not quite like the t5, but close enough for me. And secondly, with the tank being slightly more white at the front and slightly more blue at the back than the primary led fixture, the entire tank looks like it's more than just 2' from front to back. It's just an optical illusion that our brain sees the bluier water as being further away (as in scuba diving).
