Join Date: Nov 2011
Location: Winnipeg, Canada
Well it depends on spacing as well, but for example i am using 60 deg optics 12" above substrate with 5" spacingide to side, front to back spacing is like 4" maybe. I suggest buying two options for optics, I found both times buying LEDs (got some cheap ones from aquastyleonline and cree from cutter) that the optics vary more than you'd like. For example, the pattern on the 45 deg optics i got from cutter was terrible with strange artifacts instead of a smooth spread. The 60 deg optics are fantastic. And the 80 deg optics from aquastyle just didn't seem anywhere near as bright, with a LOT more side spill than the 60.
I had a thought of using really narrow optics, like 5 degree, and mounting the LEDs recessed in (narrow) matte black tubes in the ceiling, but you'd certainly need to do some experimenting with spread and height etc to get a nice tight pool of light over the tank. But you could have "invisible" lights, although the fixture and tank would be specific to each other and rather troublesome to move. I'm going to try and get my hands on some narrow optics to try this soon-ish