So I have spent a lot of time now reading up and comparing light fixtures and the more I did the more I needed to know about the specifics of light.
I came across these 2 articles which while perhaps overly technical at times were also very helpful in explaining things and filling in the holes of what I was reading in the "marketing" world of lighting.
Anyway I thought I would share them here
*** There is a colossal amount of information in these links so scroll though the entire thing a couple to times to pick out the highlights ***
Want to know more about: Kelvin Rating, Nanometer, LUX, PAR, RQE, PAS, & PUR, Photo inhibition, Lumens, Watts, CRI, even Tank set up lighting suggestions (about 7/8th of the way down the page) and what happens to light going though a Plexiglas lid?
Aquarium Lighting Information Guide | Reef Planted | PAR PUR/PAS
Even more specifics on PUR, PAS and PAR in regards to water depths along with links to other resources.
PUR, PAS, PAR in Aquarium Reef/Planted Lighting; LED Wavelengths
Anyway I have found a lot of great stuff on The Planted Tank and figured I'd share these because I also found them useful.