mrg02d
Aquarium Advice FINatic
Since I guess you're using optics, it would seem that you'll need to add more leds to prevent spotlighting?
Im not using optics, I was suggesting them for a tank with a depth of more than 17in or so based soley on my observations. You may need more leds if you use optics with much less divergeance than a bare led.
You can work it out using some trig and the angle of the optic. There is also a chart somewhere on the net that shows the PAR of these leds with optics at different depths. I cant remember where I found it. Probably over at nano-reefs though.
Matt