From: "Daniel Larsson" <defdac at hotmail_com>
Reply-To: aquatic plants digest <aquatic-plants at actwin_com>
To: <aquatic-plants at actwin_com>
Subject: Re: [APD] PUR-efficiencies
Date: Wed, 20 Jul 2005 08:31:56 +0200
Where did you get it from and who did the measurements?
I calculate them myself with a home-made Java-application. I input
the spectrum as a black and white jpg, the lumens, the watt and the
range, and out comes the PUR-efficiency. I've been thinking of making
it a servlet on my blog, but it requires that the spectrum is completely
black and white and it's actually more difficult than one might think to
make it so 8) I will have to make a spectrum-editing-tutorial if so.
The measurements are from email-correspondance with manufacturers
or their online data. Some manufacturers data seems very off, like
the AB Aqualine lumen-values and the spectrum changes over time,
but I take the values more of a hint of a bulbs performance. I know
that if I calculate a bulb to have 0.2 in PUR-efficiency it will be very
bad. Around 0.5 a shrug and over 0.8 really good.
Most often I choose the light I like. Aquarelle/Aquastar/Triton I like,
and they are very good att growing plants.
Do you have access to PUR data from other bulbs/manufacturers?
Only through Google or mail. All I need is the spectrum, lumens and
How does the spectrum output of the aquarelle saurama look to the human
Samu Saurama is a Finnish aquarist that made a visual bulb comparison:
The cool thing about that is that he also sampled the spectrums, so
all the bulbs are measured in the exact same way. If he also had
measured the lumens-output and the bulbs were all the same age,
the PUR-efficiency-calculation would have been a very truthful
comparison of those bulbs.
If you have a photosynthesis action spectrum for a specific red plant,
or for one specific coral it is also easy to recalculate all the
efficiencies to get the best bulb for that plant/coral.
// Daniel. _______________________________________________
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