# Lighting questions (mostly LED)



## oyf709 (Sep 18, 2010)

I do have couple of my own question need some experts' help.
1)Does brighter light = higher PAR?
This sounds like a easy question but maybe I am confused,it seems hard to answer. Comparing a 400W 6500k MH to a 400w 20000K, of course the 6500k will seems to be brighter and because the 400w 20000k is much more blue colour than the 6500k it will not look as bright. However, does it mean the PAR for the 20000k is less than the 6500k? I know 6500k will have higher Lux or Lumen reading.

2) I start to see more and more manufactors add different colour LEDs to their fixture. few ears back, there is only blue and white mostly.
But now regardless if it is brand name LED fixture or those no-name LED fixture. 
a)I saw they added mostly the violet colour which pushes the PAR reading a lot higher. For the LED light I am selling for example, same 144w LED fixture. 1 is 24x3w 12000k white LED and 24x 3w Blue LED, the other is 24x3w 12000K white and 20x3w blue, but added 4x3w violet LED. The PAR reading at surface , the one with violet is almost 400 higher. and at 27inch deep, the one with violet is close to 100 Par higher. Is it really violet light pushes PAR reading that much higer? Is it good for coral/fish?

b) not only violet, some LEDs fixtures has green/red LED in the light, I thought those promo algea growth. but why are ppl add these LED into a marine fixtures? Even tho they only has about 3 red and 3 green out of like 70 LEDS, are there any other purpose for this?


Thanks for anyone reading this and helping me solving these questions. =)


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