LED layout

[fishay]

I'm building a led fixture for a 20g long I'll be setting up soon. I've purchased a cree 24 led kit with 16 royal blues and 8 neutral whites. I'll be using a 20" x 6" heatsink.

Should I go with clusters of LEDs or an even layout? Spacing between LEDs would be about 2.5" for the even layout. If I went with cluster layout, spacing would be roughly 4" between clusters.

http://i45.tinypic.com/2s1q9eo.jpg

[Cal_stir]

less chance of spot lighting with the even layout.

[fishay]

with an even layout will I get the disco effect with 2.5" spacing?

[Cal_stir]

I have 72 leds on a 48"x12" heatsink evenly spaced @ 2.5" apart and there is no disco or spotlighting effect.
I have no optics and light is 4" above the water.

9711

9712

[fishay]

Good to know...the only reason I was considering clusters was to get the colors to blend well enough that theres no disco. Thanks

[Cal_stir]

in that photo the light has 36 xpg cool white and 27 xpe royal blue and 9 blue, I just popped 12 of the whites off and replaced them with xte royal blue, still no probs with colour mixing.