Re: Effects of light on fry color development

[Wright Huntley <jwwiii at pacbell_net>]

MDelra at aol_com wrote:
> Wright, quite awhile ago, when I was in the business, we also used Chroma 75 
> bulbs in combination with Chroma 50 and Growlux.  The idea was that the Chroma 
> 50 peaked at the blue side 

Hardly. The reason for the color temperature being 5000K (that's what the 
50 stands for) is because it is strong in the red end and weaker in blue.


and the Chroma 75 the red.i.e., the two peak
> wavelengths required for photosynthysis. 

At 7500K the Chroma 75 would have the increased blue component.

> I dont remember the exact wavelengths, but 
> somewhere around 4500A for blue and 6800A for the red.  

The action spectrum for plants is not a narrow wavelength, but a spectral 
distribution. It has some value everywhere in and near the visible 
spectrum, but with a weak hump in the blue region around 450nm and a far 
stronger one around 700 nm in the deep red. It dips pretty low in the 
green, around 520nm.

Lighting for best plant efficiency would give you a disgusting 
purple/magenta hue that would not make for a pleasing tank viewing 
experience. Compromise between what you need to see and what the plants 
like. That works best, for most folks.


> I did an experiment 
> with a 100 gallon tank and lighting: Actinic, Chroma50 , GrowLux, And Chroma75, 
> plus diffuse room lighting(living room). The plants were growing out of the 
> tank.  It was back when the reef people dominated the aquarium literature with 
> alternatives to the Dupla system. The tank had Arnoldicthys spilopterous, 
> Synodontis decorus, Congos, Nanatheiops, Epiplatys zimienses to mention a few. The 
> lillies bloomed for about a week and the Amannia bloomed once. All the 
> anubias began to grow out of the tank with the exception of A. nana which quickly 
> crept along the bottom into a mat.  Why you ask, did I tear the tank down?  My 1 
> year old began yanking on hoses, etc. The wife made the decision: Fish stay 
> in the basement!
>
> Did you ever use those actinics on freshwater aquaria?

The 10,000K lamps for reefs are not very useful for plants. Some look 
pretty white, but they tend to lack enough red light for really good 
photosynthesis. They can improve visibility, when combined with "warmer" 
colored lamps that make up the red shortage.

I like 6500K or 5000K CFs in 36, 55, or 96W, if they have a CRI above 80 
or so. In an AH "Brite Kit" they can heat the tank less and provide the 
most efficient illumination, because of the efficient and well-designed 
reflectors that are available nowhere else.

Wright

--
Wright Huntley -- 760 872-3995 -- Rt. 001 Box K36, Bishop CA 93514




---------------
See http://www.aka.org/pages/killietalk/subkillietalk.html to unsubscribe
Join the AKA at http://www.aka.org/pages/join.html