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Re: Aquatic Plants Digest V2 #655

> Date: Thu, 17 Apr 1997 22:30:14 -0400
> From: krandall at world_std.com
> Subject: Sufficient lighting
> Karl wrote (sorry for the delayed response, but I've had a busy few days!<g>)
> >The wattage formula of 2W/gal or 3W/gal is adequate to determine the proper
> >lighting when using tubes, however I still believe it is necessary to
> >investigate the Color Rendition Index of said tubes to get at least some idea
> >of where you're going.  In my calls to lighting dealers I have never had much
> >trouble obtaining this information.
> Actually, from what I've read, I believe that CRI is more useful in terms
> of what the human eye sees than it is for determining whether the bulb will
> meet the needs of the plant.  The most important from the PLANTS'
> perspective is that the light is intense enough, and that the spectral
> distribution is an "M" shape, whith most of the light in the red and blue
> areas.  While plants can use SOME light in the yellow/green area, algae
> seems to be able to ulitize it better.  If you don't have much algae, it's
> probably not going to be a problem, but if you are battling an algae
> infestation, you are probably better off with the "M" shaped spectral curve.


No argument there!  The spectrum is important.  What I have found in many cases
is that a high CRI rated tube (generally) is a full spectrum tube.  So, maybe
what the human eye sees is ok.  8-)