Re: [APD] Re: Lighting

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

sh
--- Daniel Larsson <defdac at hotmail_com> wrote:


> Nevertheless I really think the lumens and spectral
> distributions
> are easier to quantify than just looking at Karen
> Randalls
> aquariums?
he he he. Nothing is easier than looking at Karen's
aquaria. But that's not meant as an argument ;-)

The ability to quantify some things and discarding the
things that are in principle quantifialbe but as a matter
of practicality aren't easily assigned values doesn't
necessarily improve calculations -- it just simplifies the
model to fit the math. 

I'm not saying it's all a waste of time, I'm just saying
that a newbie should not think that a choice of flo bulb is
going to make or break her or his gardening. 

> I also strongly believe that the lumens-ratings are not
> made
> up, and even if they are measured differently between 
> different manufacturers I would guess they're off by
> a just some percent - about the same error as your
> Karen-measurements would be? ;)
> 

Not made up -- but it complicates the calculations if the
issue is addressed. A flo bulb loses roughly 20% it's
initial brightness in the first few hundred hours -- the
rate of dimming becomes more gradual over time. So giving a
lumen rating after 20 hours, 100 hours, 200 ours, or 500
hours burn-in can make a signif diff. There's no standard
burn-in period that manufacturers have to use to when they
give lumen ratings for flo bulbs.

> 
> These numbers are not for noobs to be anal about, but
> it's interesting to make a calculation on a bulb someone
> says is good for growth and see if that is somewhat
> , off by some percent, true. Or if the persons is lying
> you right in the face.

Yes, and there are deceptions worse than lies. A
salesperson in a lfs once told me the remarkable thing
about Eheim filters that made them superior to other
filters is that the pump had "only one moving part."  All
small electrical motors have one moving part, the rotor,
and a stationary part, the stator. Manufacturers claims,
Eheim pump rates notwithstanding ( ;-) ), are often factual
but not necessarily comparable without some adjustment. 


> It is also interesting because if you really get the
> calculations behind the scenes you will have deeper
> understanding whats going on both in the bulbs and in 
> the plants. You will understand why the lumens-
> measurement can't be used, alone, to estimate if the 
> bulb is good or not for plant growth. 

Actually, you can and many have for years. Wpg works out
pretty good for aquatic gardening purposes. If you hear
someone say, "Turns out the reason I couldn't garden worth
a tinker's dam is that I was using plain ol' shop lights
from home depot," look into the gardening techiniques and
I'll bet you'll find other more serious problems that the
person wasn't addressing. And it's not difficult to fit in
as much light as anyone could seriously want with the lamps
available today pretty mcuh regardless of the brand  of
bulb.

Standardized data would be great, but I don't see that we
have it yet. However, it isn't likely to make so much diff
that a newbie needs to worry about it. Develop a
maintenance routine then worry about the tweaks.

Some flo bulbs better than others? Sure. About all of them
will work fairly well? You bet!

sh

=====
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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