very nice build theblondskeleton i love it , i am on my way to make my lights for the same tank as you , well i have some questions you are running 28 CREE XTE leds but at what current ? and is by that you are getting enough light for a high tech system ? and about your NW leds how much its kelvin ?
and after your experiment what do you recommend for the ratio between CW and NW
Thanks! I can't say how much I love the heat sink. It's a pretty well engineered package.
I'm running 36 emitters now (after adding the 8 warm whites). My driver is the SmartyCat designed by O2Surplus (see his thread about that). As I recall, it runs at about 1100 mA, but I have each channel manually dialed down quite a bit. I couldn't say exactly what the current is for each channel, except to say it provides plenty of PAR without algae issues.
As for the ratio of cw/nw, I'd say add the warm whites to the equation. Without them I was getting leggy growth that looked like I just didn't have enough light (which I didn't in the red part of the spectrum). My current ratio is (cw:nw:ww) 1:1:0.5, but my cw are running at about 75%, my nw are dialed down at least 50%, and the ww are running at nearly 100% (of the 1100mA max). They also have 80 degree optics instead of 60 degree optics like the cw/nw.
In other words, a lot of variables going on there.
I'd almost say you don't need nw, except to render your greens. That would be a personal choice.
Those are just my observations based on my conditions, so things may be different for you. Hope that helps!