Re: [APD] light

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

I agree that there is little to be achieved in trying to finesse the bulbs too much -- little unless the finessing is the part one enjoys most. This seems especially given that much of the specs that are reported are not measured/reported consistently, some of the fine details change over the life of the bulb but not necessarily linearly, etc.
 
Unless the finessing is the part one has fun with, general rules of thumb allow for a more enjoyable hobbying than do incredibly precise technical goals. I urge the batter to try to hit the ball solidly and have fun; I don't urge a batter to put the ball 3 feet behind the shortstop's left shoulder.
 
sh
 
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----- Original Message ----
From: Thomas Barr <tcbiii at yahoo_com>
To: aquatic-plants at actwin_com
Sent: Sunday, March 19, 2006 3:06:33 AM
Subject: Re: [APD] light


Scott, there is a slight dip in the quantum yield and O2
evolution in the range from about 450-600nm, maybe 10-20% at
most for quite a few plant species, as well as algae.
There are quite a few pigments that make up the LHC(light
harvesting complex). Carotinoids are also variable, chromatic
adaptation.........as are various other pigments.

All light that is used in PS is 680 or 700nm or higher.
When light is captured, say Blue light, say at 425nm, what do
you think happens? It loses energy and casacades down to P680*
Chl and then enters PSII. 

So the green light, with a little less absorption ability, still
requires some loss, but less than blue light.

HPS bulbs grow plants so well since most of the color is Yellow
and red. It loses less energy to grow the plants.

A lot of light is not captured as well.
Wasted light.......

Given the many issues, I think the color temps, the blue/red
mix, the non algae promoting blah blah light, is not really an
issue, never really was, main thing have enough intensity, have
enough color rendition to be pleasing to our eyes.

I think too many get fooled with light bulb marketing and
efficiencies etc..........get a nice color bulb that looks good,
PC's, T5, HQI's, MH's, NO FL's all do very well and look good.

And that's what most hobbyist use......

Still, most folks don't like a green light in their tank.
So I do not think green light will ever be a threat:)

Regards, 
Tom Barr

www.BarrReport.com


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