Re: [APD] Re: Lighting

["S. Hieber" <shieber at yahoo_com>]

It's hard to disagree with numbers but not so hard to
disagree with their application.

Things that probably will matter as much or more for
lighting are the particular ballast used with a partiuclar
lamp, the lamp (reflector) and bulb combination, hours of
illumination, and whether the *manufacturer's* rating for
output is based on post-burn-in and if so, how many hours
after burn-in. Over and above this, nutrient levels,
including CO2, and maintenance habits of the gardener may
have effects that swamp the diffs between this bulb or
that.

Ivo has done some excellent work and I do not mean to
detract from that. However, I think it is important to
remember that the rough rule of thumb based on wpg will
serve most aquatic gardeners about as well as any other
available measure -- it doesn't have to be complicated. By
all means, use Ivo's results if they list the bulbs among
which you are making your choices, but keep in mind that
the playing field isn't quite level to start with, for the
reasons mentioned above, and the impact on your aquarium
might not be quite like what Ivo's numbers predict.

Karen Randall can do an enormously better job of growing a
beautiful garden with some shop lights than I can with a
set of the best bulbs on Ivo's list. Bulb choice need not
be something over which to suffer angst.

Scott H.
--- Daniel Larsson <defdac at hotmail_com> wrote:

> Lief Brittan Youngs wrote:
> >Is there a measurement that is best? 
> 
> Yes, there are better measurements than wpg.
> Ivo Busko calculated PUR-efficiency, and I did
> a Java-calculator where I input the spectrum, initial
> lumens and watts and it calculates the bulbs
> PUR-efficiency.
> 
> PUR-efficiency tells you in one number how
> efficiently the bulb outputs it's energy in
> the area of the photosynthetic action spectrum.
> 
> You can read how it's done here (last in the
> article):
> http://www.aquabotanic.com/lightcompare.htm
> 
> 
> >(Kelvins, watts, etc.) It seems that what 
> >was said is that the color of the bulb 
> >doesn't really matter as much as the watts 
> >per gallon. Is this true?
> 
> Both yes and now. Color in one number such
> as Kelvin doesn't say a thing. But color in the
> form of hundres of numbers like in a spectrum
> tells you much. You can calculate how efficiently
> the bulb converts watts/energy to lumens and 
> with this effeciency  you can calculate how
> well the spectrum conforms to the photosynthetic
> action spectrum, which roughly gives you how
> "hard" the bulb is hitting on the vital parts of the
> plant ;)
> 
> You can send me spectrums+watt+lumens of
> the bulb you would like to calculate PUR-efficiency
> for. 
> 
> Ivo: If you're reading this, please contact me
> off list. I would like to discuss the calculator.
> 
> 
> // Daniel.
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> 


=====
Plant your feet in Washington, D.C. and touch the moon -- at the National Air & Space Museum. 
And learn the art of aquascaping Senske style at AGA2K4. 

Speakers, field trip, Ray "Kingfish" Lucas, and more. . .
The Annual AGA Convention, 2004, November 12-14.

Convention Details/Registration at aquatic-gardeners.org & gwapa.org
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