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Re: NA Fluorescent Lights

>Date: Mon, 21 Jul 1997 07:22:40 -0400
>From: Arturo Giacosa <agiacos3 at ix_netcom.com>
>Subject: Re: NA Fluorescent Lights
>Blue/green light has been shown to refract less than the other colors so
>it reaches down deep into the aquarium.  ADA's research shows that in
>nature, aquatic plants receive this color spectrum and have adapted to
>using it.

Sorry Art, but blue light is actually refracted more (ie. it has a higher
index of refraction) than light at the red end of the visible spectrum.
Take a look at a typical glass prism, and you will see that violet is
"bent" the most and red the least.  Also, remember that refraction only
happens at a surface.  It is not dependent on depth.  Refraction does not
reduce the intensity of light passing through a substance, it only changes
its direction. 

If blue light penetrates further into a particular water column it is
because it is absorbed and/or scattered less than red, not because of
refraction.  Of course, this depends on what is in the water.  Some
natural, and aquarium, waters will transmit more red than blue...