Originally Posted by Biggen
I will tell you guys that WPG
is a terrible way to attempt to gauge a tanks success at keeping corals.
Which is why I also included par in the original reply.
I am a believer in the "blue" tank. While PAR is reduced when going to higher spectrum bulbs, I think the "blue" effect is not only pleasing on the eyes, but seems to help the corals as well.
There are two scientific ways to measure light.
Lux: This is what we generally refer to when we say wattage. Its the difference between a 40 watt bulb and a 250 watt bulb. To the human eye, the 550nm range is the wavelenghth that we see as the brightest.
Par: is photosynthetic Available Radiation or what your corals need to carry out photosynthesis. For our purposes, its the intensity of the of the usable light as it travels deeper through the water. Par is important for several reasons. It tells us which light is best suited for our corals, it tells manufactures how to avoid a yellow looking bulb (550nm wave length appears yellow)
Bang Guy gave this example:
"An example would be a 110 watt URI VHO
actinic bulb. It has 1/10th the lumens of a standard daylight florescent bulb but 2 1/2 times the PAR.
If you just went by Lumens then the Actinic bulb would appear to be useless for a reef tank."
Its my understanding that the best par rating (top to bottom) is
M/h, T5, VHO
and P/C, and then N/O.
Now...throw in the last kink in the whole thing, the K
is what tells you what color the light is. Nothing else. Sunlight is 5.5 K
(if I remember correctly.) The closer to 0 you get the more yellow the light.
Wow....I'm outta breath. Did that make sense?