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Re: [APD] Re: Lighting

Well, that would be the real test, wouldn't it? Doesn't
seem like an odd thought to me at all. It would obviate
accounting for diffs in manufacturers' rating methods. 

But maybe hard to set up, hard to control all the
conditions that you don't want interfering with the test
results -- which is to say, the impact of other things
might swamp those due to diffs between some (many?) bulbs. 

One would need a lot of tanks, time, or probably both. And
then, if you changed electronic ballasts, that might change
the results since they don't all drive at the same
frequency and voltage or pass the same amount of current
through a given bulb. Conceivabley, a bulb that performs
less well than another when slightly underdriven (on one
ballast) might perform better than the other when driven
harder (with a diff ballast). [Even incandescents have a
spectral shift depending on how hard one drives them.] I
think one would want to test for diff ballasts too.

Short of that kind of "actual" results experiment, Ivo's
method is easier to do. The Ivo method would be, imo, much
better if any diffs in rating methods could be accounted
for. But doing that might not be any easier than doing the
"actual" results experiment.

Surely, time, and a lot more effort will tell.

Scottt H.

--- Matthew Andrews <matt at slackers_net> wrote:

> Odd thought:
> when attempting to determine what bulbs are best for
> growing plants why 
> not forget about all the spectral
> output/lumens-ratings/watts efficiency 
> calculations, and instead set up a growth efficiency
> test.
> chose a set of standard test plants, a standard growing
> setup(balast, 
> tank, substrate, fertilization reflector etc. something
> that anyone 
> interested in testing bulbs available them can
> acquire/build) and a 
> procedure for measuring amount of plant growth. that way
> we can say 
> plant species 'X' gained y% more mass due to new growth
> under bulb A 
> than it did under bulb B.
> -Matt
> Daniel Larsson wrote:
> >sh wrote:
> >  
> >
> >>It was just becasue of the problem of diff test
> conditions
> >>that the feds set up a standardized method for the
> stated
> >>fuel economy ratings.
> >>    
> >>
> >
> >Nevertheless I really think the lumens and spectral
> distributions
> >are easier to quantify than just looking at Karen
> Randalls
> >aquariums?
> >
> >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? ;)
> >
> >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.
> >
> >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. You will know
> >why the lumens-measurement together with the wattage-
> >rating can be used in conjunction with the spectral
> >distribution to make a rather good estimate how good
> >the bulb light is for growing plants. With this
> knowledge
> >I can kick back, forget about the lights and just see to
> >that the plants isn't shading each other and start to
> fiddle
> >out my dosing regime and put all the efforts where it
> >should have been from start: On CO2.
> >
> >Then I, as a noob, will have pretty good growth, off
> >by some percent.
> >
> >
> >// Daniel.
> >
> >
> >_______________________________________________
> >Aquatic-Plants mailing list
> >Aquatic-Plants at actwin_com
> >
> >
> >  
> >
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