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Re: Aquatic Plants Digest V3 #673

At 03:48 PM 11/28/98 -0500, Tom Barr noticed:
>they(QTL's) to grow plants of many varieties at much faster rates . I
>have 80w of FL's on and 150w of QTL's on the same tanks. The lumens
>should be 2400 for QTL's and aleast 6000+ for the FL's yet the rates are
>slower for FL's.

Well, this brings up a couple of questions.  I have no reason to disbelieve
Tom, he is a pretty careful observer.  Note that the FLs are weighted by
LUMENS, PAR might be more appropriate.  But even more appropriate would be
growth rates.  Which is what Tom has noticed.

I think we all await the outcome of his careful split-tank aquarium with
great anticipation.

Supposing the above observations hold.  Then how to explain this.  No one
has "proved" that 3000K incandescents don't do an exceptional job of
driving chlorophylls, have they?  Maybe the incandescent has just the right
spectrum.  And maybe the problems with controlling heat explain why
historically incandescent hasn't been favored.   Quartz tubes can run MUCH
hotter, so that innovation may lead to high illumination densities.  


Dave Gomberg, San Francisco            mailto:gomberg at wcf_com