Re: [GSAS-Member] CFL bulbs

[Erik Olson <erik@thekrib.com>]

the kelvin rating is a measure of color -- the larger the number, the more 
blueish the spectrum.  The lower the number, the more yellow-reddish.

We don't use wavelength directly as a measure of the bulb, because the 
bulb is not emitting monochromatic (one color) light, but a spectrum of 
white light across many wavelengths.  The color temperature is just a 
measure of the relative amounts of the different wavelengths.

The sun is between 5500-6500K in its color temperature

   - Erik

On Thu, 22 Oct 2009, naturalart@earthlink.net wrote:

> Shango, all I can tell you is that 10,000kelvin bulbs tend to have more
> blue in their color spectrum. Blue penetrates further than red or
> yellow. But plant growth is weak/ 'spindley' under blue light. The
> 6500-6700 bulbs have more red/yellow in spectrum. Weather kelvin and
> wavelength are independent of each other I dont remember, maybe someone
> else can speak to that. But if I were to buy one bulb for my freshwater
> plant tanks I would buy the 6500-6700, more effective color spectrum.
>
> Clay A.
>
> On Thursday, October 22, 2009, at 08:24  AM,
> gsas-member-request@thekrib.com wrote:
>
>> So this discussion brings backs a topic I have yet to find a decent
>> answer to.  I get differing answers from every source.
>>
>> Most of my fixtures have room for two bulbs.  I have bought one
>> 10,000K  so the tank looks good to my eyes and then the second bulb is
>> 6700K so the plants thrive.  I am not sure this is accurate though.
>>
>> Now, I am looking at buying this 6500K bulb.  Why isn't it 6700K?  If
>> 6500K is better for plants, then why isn;' Coralife producing a 6500K
>> bulb instead of 6700K?
>>
>> AND, if I only get one bulb in some of my fixtures, do I get the 6500
>> over the 10,000 because it is a planted take?
>>
>> Can anyone give me some good perspective on this?
>
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-- 
Erik Olson                                                        Sent from my 
crusty old Linux box
erik at thekrib dot com
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