Re: Inefficiency of Blue Light

To: Aquatic plants list <aquatic-plants at actwin_com>
Subject: Re: Inefficiency of Blue Light
From: Cynthia Powers <cyn at metronet_com>
Date: Mon, 18 Nov 1996 17:26:17 -0600 (CST)

---------- Forwarded message ----------
Date: Mon, 18 Nov 1996 16:36:00 -0500
From: "K & A, P.A." <kapa at netrunner_net>
Reply-To: kapa at netrunner_net
To: Aquatic-Plants at ActWin_com
Subject: Re: Inefficiency of Blue Light

In response to Diana Walstad's recent query regarding blue light:

Diana,

I use one actinic bulb in combination with several full spectrum bulbs
in some of my tanks.  Ususally, because I feel that I don't have enough
light over the foreground and don't want to spend the money on metal
halide or the like.

It has been my experience that the actinic blue puts more light (amount
or lux) than regular full spectrums on the actual leaves of the
foreground plants.  The reasoning being that the blue reaches farther
through water.

I think you are right in that aquatic plants may not use light in the
blue spectrum as efficiently, but the fact that you are getting greater
lux on the plant, I believe, compensates for this.  As you know, there
have been studies (Philips) that conclude that almost any light will
grow plants if sufficiently supplied.

It is important to maintain a close watch over all other variables,
however.  Since algae can probably use this light better than can
plants, and any disturbance with regards to trace elements, CO2,
phosphate or nitrate will probably lead to algal growth.

Additionally, making the actinic turn on 30 minutes before and after the
daylight cycle gives the illusion of a dawn and dusk.  The fish really
seem to enjoy it and it is nice to watch.  Also, Amano has used lamps
high in blue/green (8000K) with great success.

Just to be clear, all of the above is just my opinion based on my
experience.

Art Giacosa