[KamelRedLight]

I don't really know. My guess is there's little difference, but from a couple graphs Ive seen of 5500k, theoreticallly there can be a noticeable advantage to using 6500k. I notice that a lot of graphs of the same exact color temp vary from one manufacturer to another, or maybe it's just the graphs themselves, but generally 5500k wastes a little more light in the yellow/green area than does 6500k. Wish I could experiment some more. Funny that now ledgrowlights.com is giving me an awesome offer on their lights. I wonder if I should buy new ones and just hold onto em for future projects, or if I'm gonna find that once I can grow again, LED's will be cheaper than CFLs. That sounds more like my luck.