> From: Erik Olson <olson at phys_washington.edu>
> Date: Sat, 13 May 1995 08:46:02 -0700 (PDT)
> Subject: Re: Aquatic Plants Digest V1 #67
> > From: Mark Wickersham <mwickers at minerva_cis.yale.edu>
> > Date: Fri, 12 May 1995 22:44:01 -0400 (EDT)
> > Subject: More on E.tenellus; [blank]-Glo bulbs?
> > 2) The shopkeeper with whom I discussed the above discrepancy in
> > references claimed that I could vastly improve my lighting performance by
> > purchasing a Life-Glo bulb: 20W, 24", but it has 240 Lux! Biolume, in
> > comparison, apparently only gives 80 lux. Am I missing something?
> FYI, Usually we barter in Lumens, not Lux. But this sounds inherently wrong.
Hmm. I just reread Booth's article, to which you referred me in response
to my first question, and it gives Lux values for all of his bulb tests,
not lumens. According to Barry James's book, "The amount of light
reaching a surface is measured in lux, which is equivalent to lumens per
square meter." The principal reason I used lux in this question was
because that was the only striking difference in the manufacturer's specs
between its several bulbs. All the lumens were approximately the same.
So what I was specifically wondering was whether focusing the output, as
this light seems to do, is helpful. Booth's analysis in his several
interesting articles seems to show that internal reflectors are not worth
the extra expense. He compared the Biolume (that's what I've been using;
it has a built-in reflector) with the Trilux, and discovered that it
does not perform favorably. At the shop selling these Life-Glo bulbs,
though, there was no question that the light was *much* brighter coming
from the Life-Glo than from a new Triton (also a bulb I have used' it,
too, has an internal reflector). Booth's article also compared the
Power-Glo with several other bulbs, measuring primarily their color
temperature. Unfortunately, his articles do not address the Life-Glo
bulb, which, again, is the only [blank]-Glo bulb that has this intense
It is obvious to me that there is no way of getting around the need for
multiple bulbs, and eventually that is what I will do, but until then I
was hoping for better plant growth with minimal outlay. (I am stuck with
my single-bulb strip light that fits my Perfecto hood which I purchased
well before I discovered that plants were not as difficult as unearthing
the holy grail.) I will probably invest in an Ultra Trilux next, judging
from the results of Booth's tests.