Take with a grain of salt because I am researching as well:
- For white LEDs look for high CRI (color rendering index). 80 or higher ideally.
- Cree is the most popular at the moment because of a combination of quality color (i think CRI), efficiency (lumens per watt) and price. The impression I get is stick with Crees and you'll be safe. If you are willing to invest the time in research and experimentation you might be able to optimize one of cost/efficiency/color with other options.
- Bridgelux - sounds like some of the emitters are not very good (not sure why) while others are really good. There is a thread on nano-reef about the "evil cluster" using a large Bridgelux emitter.
- Some advice from Dave Fason of nano-box: choose Cree, Philips Luxeon Rebels or the commercial Bridgelux emitters for whites. For blues there are more options that are pretty good like some Chinese designed emitters.
- Meanwells are the Crees at the moment. Good quality, reasonable price. A safe choice. Inventronics and Thomas Research are supposed to be better quality. TR has some nice features like waterproofing and short circuit protection. But most builds are still using Meanwells.
- As for what colors to use and their ratios... from what I've read somewhere between 1:1 and 1:2 neutral white to royal blue is a good starting point. Ideally, whites and blues can be dimmed independently so you can choose your color. If you are willing to add the complexity, add a small amount cool blue, deep red and true violet. The problem with color is it is both subjective and depends on what you have in your tank. Check out the LED asthetic thread on nano-reef.
I feel your pain. There isn't a good guide on DIY led. You have to wade through thousands of posts and synthesize yourself. If you want a safe option, buy from modularled. If you want the best option (for you) keep reading
