Question for the LED experts out there

[stage3-S4]

Hi all, I'm setting up a new cube tank thats around 25 gallons(18x18x18). I was just wondering if anyone had any ideas as to how many Cree XR-E leds I should use. Right now I have a fixture of 6 royal blues and 6 cool whites. Over the empty tank it seems more then enough but I don't know how it will be with a tank filled with water. I'm looking to keep sps and some lps in the tank. I was thinking of adding another 12 leds. Do you think this will be to bright? Any advice would be appricated.

 

[OOtzie]

I have 12, I run 8 blue and 4 white on my 14gal cube. If you add 4 more blues making it 10 blue and 6 whites you'll be able to run anything.

 

[stage3-S4]

I have 12, I run 8 blue and 4 white on my 14gal cube. If you add 4 more blues making it 10 blue and 6 whites you'll be able to run anything.

I mean at that point I might as well just add 6 more since i would have to use another buck puck. I was thinking of adding maybe 3 neutral whites and 3 475nm blues to give it a broader spectrum. Right now it has more colors in the upper specktrum.

 

[smoq]

Check my thread that will give you a general idea http://www.manhattanreefs.com/forum/diy-do-yourself/81156-cree-led-light-write-up.html. My tank is 20x20" and I would use 24 leds and dim them if needed.

 

[stage3-S4]

Ok I think I may just do that. I may add in some neutral whites to broaden the spectrum. Also I noticed that the huge heatsinks are overkill. I don't even have a fan on mine, and it never even gets warm. I did some thermal calculations and as long as the junction temperature of the diode doesn't reach above 125 degrees c, you are golden. I wish I new this before I spent 50 bucks on my heatsink lol.