I have 250 watt mh
. I originally had 10,000k and one burned out. I was going to replace with 14,000k for both. One of those burned out within a few days so I now have one of each. That being said, my point is that the 14,000k bulb has a much whiter/blue light and the 10,000k is almost yellow in comparison. Therefore, I am pretty sure that the kelvin rating also has something to do with the visual spectrum to the human eye.