Good link. I recently noticed I was getting too much of a "point source" effect in my tank with the LED fixture I'm running. I tried raising the fixture, which helped a little, but it's still noticeable and measurable with a PAR meter. I thought that maybe the glass lid was a factor, but it's actually worse without the glass diffusing some of the light...go figure.
I plan on switching to just T5s within the next week or so, then may incorporate some supplemental blue LEDs for color. Having measured the PAR levels with both the T5s and the LEDs...I definitely noticed a more even spread with the T5s in the 12" deep tank. The PAR numbers were much more intense toward the surface with LEDs (probably why I lost a couple frags of zoas), and there were some areas directly under the strip of white LEDs that were significantly higher than an inch or so to either side. Raising the fixture did help the spread and muted that effect, but I then end up with waaaay too much light spill in the room if I raise the light to an acceptable height.
I do plan on going with LEDs again on my next build...it's a toss up between the AIs and the radion at this point.
