Cree LED questions

[raistlarn]

Well to start out the tank I am going to build a LED fixture for a 30g aquarium which is 36"x12"x16". I want to keep LPS, zoanthids, and clams; and eventually move up to SPS corals.

I want to use the Cree XM-L LEDs but I don't know how many I can safely put over a 30g aquarium without killing off coral.
Which drivers would work with XM-Ls as well as be dimable and affordable?
What color ratio would work best using XM-Ls and RB?
And my final question is should I use a row of LEDs in a line or make 3 LED pucks on a 4.25" x 23" heatsink.

[evilc66]

Why do you specifically want to use the XM-L? Honestly, for a tank of your size, it's not necessary. It's not like you are going to use fewer LEDs when compared to XP-Gs. An XP-G and XP-E setup will do everything you want, and more, and cost less than the XM-L setup.

If you want to go with a traditional grid style setup, you can easily light that tank with 24 LEDs in a 12x2 setup. That will keep everything and anything you could possibly want when driven up to 1000mA. I advise getting dimmable drivers so you can easily set the color temperature, and the overall intensity to suit the needs of the tank.

[raistlarn]

Ok thanks for the reply I just ordered the XP series of cree leds. I ordered a 2:1 mix of RB to NW and was wondering if staggering them like this would work.
RB,RB,NW,RB,RB,NW,RB,RB,NW,RB,RB,NW
NW,RB,RB,NW,RB,RB,NW,RB,RB,NW,RB,RB

Or would a 3 led cluster w/ 80* optics work, and if I were to go with option 2 what would be the best distance to space the clusters from each other.

[evilc66]

Either way will work, but you shouldn't need to use optics unless you are mounting them somewhat high over the tank.

If you cluster the LEDs, spacing of 3-4" should work fine.