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Re: lighting small tanks, watts per gallon rule?
<Power spectrum is (relative) Watts vs inverse frequency (or wavelength). All
<lamp outfits use that standard format.
Not true. Every one I have seen has no units up the Y axis just percentage
values. If you can direct me to charts that plot watts versus frequency I would
greatly appreciate it.
<It *can't* be expressed in "lumens" vs frequency, for lumens -- by
<have a particular spectrum built in.
This is of course quite incorrect. For any given freqency lumens can can be
converted to either watts or PAR values. If you say spectrum charts are given in
watts then they could be converted to lumens.
<PAR is only a bit better, for it assumes a wider spectrum, but rarely does it
<agree very well with the action spectrum of *your* particular plants, anyway.
<Again, no such thing as PAR vs frequency. Same reason.
Also incorrect. PAR and the visible spectrum are virtually coincident. Also, how
can know that PAR agrees or disagrees with my plants since I cannot find out
what what my lights are emitting. Again, you can plot PAR versus frequency. Same
<Einsteins count photons, and photons have different energy at different
<wavelenths, so a "spectrum" of Einsteins vs frequency would have the frequency
<squared and look pretty strange if not totally useless.
My mistake I can't put one over on you. The chart I would like to see is
photonic flux versus "inverse" frequency and this chart would look pretty good
to me. In fact, it would look pretty much like the elusive watts versus
"inverse" frequency chart except that it would be more heavily weighted toward
the red end of the spectrum.
<Wrong. It gives us an excellent *indirect* clue. The good tubes that have lower
<lumens/Watt are usually putting more energy in the ends of the spectrum where
<plants are more growth active, and less in the more visible green region. Tubes
<with high lumens/Watt will make the tank *look* brighter, but "feed" the plants
Hmm let me think. Yes, I believe you are incorrect. Typically plant and
aquarium lamps that suposedly put out only in the red and blue spectrums are
actually less effective at stimulating photosynthesis because their power output
is actually lower in the red and blue spectrums than a lamp intended for the
human eye. If only manufactuers would publish spectral charts in say, watts
versus "inverse" frequency then this would be obvious at a glance.
<Read the spectra as *relative* Watts vs inverse frequency (or wavelength) The
<peak is normalized to one, and all other values are just a percentage of that.
<[Yes, it *is* frustrating that they assume you know that and never, ever label
<the vertical axis.]
What does this goofy chart tell you? Pretty much nothing. Who cares what the
relative distribution is within a particular lamp. I want to compare one lamp to