Originally Posted by
dsmccain
http:///forum/post/3295369
I am not 100% sure on what those ratings mean, I only really understand the wattage.
Those ratings are the light spectrum. In your case the 12k is for Growth.
6,500 is an orange. 10k is more like a yellow. 14k begins leaning towards white all the way through to around 18k. 20k is a blue tint. Lights come in all sorts of spectrums in beetween. Typicly 10-14k is assoiciated with best growth. 14-16k is the happy medium(looks and growth combined). 20k is the astheticly pleasing blue color.
The 460nm super blue is going to be the "Black light" effect. Its the blue/purple light that makes the colors of the corals really glow. It doesnt do much for growth, but it really does alot to make things look pretty.
Here is an offical description cut/paste froma basic google:
Light Spectrum - Measured with the Kelvin Scale
The spectrum or "temperature" of light is measured in degrees Kelvin (K). The Kelvin scale describes the color of a light source when compared to a theoretical "blackbody." Think of a piece of steel that changes color as it is heated. The Kelvin scale does not measure the light the steel gives off as it is heated; instead it measures the color of the light being given off. Color temperature does not represent the temperature of the light source. It merely defines the color given off in comparison to a blackbody radiating at the same temperature.
At 0 degrees Kelvin (equivalent to -273° Celsius), the theoretical blackbody emits no light. As the blackbody warms, it begins emitting red light. As the blackbody continues to increase in temperature, light wavelengths become more yellow, then green, blue, and finally violet. A candle flame on the Kelvin scale has a rating of 1800 K. Sunlight at noon, with a Kelvin rating of 5500 K, is typically referred to as full spectrum because it contains a blend of all colors throughout the spectrum. Reddish light has a lower K rating and color temperature, while bluer light has a higher K rating and a higher color temperature.
In nature, as light enters and passes through the first 15 feet of water, the red and orange wavelengths are absorbed by the water, increasing the light's K rating, and giving the light a bluer appearance. As the light penetrates to 30 feet, the water absorbs the yellow spectrum. And as the light continues past 50 feet, the water filters the green wavelengths, leaving just the blue and violet wavelengths. This results in light with the highest Kelvin rating.
