Re: [APD] Help With My New Tank!! -- or - Bravely into the Shadows

[Bill Wichers <billw at waveform_net>]

----- snip 8< -----
There are several primary types of lights around, and those are 
incandescent lights (with filaments), fluorescent lights (which use a 
primary light source of one wavelength to stimulate the emission of other 
wavelengths from one or more phosphors), HID (High Intensity Discharge, or 
"arc") lights (which generate an electric arc -- basically a big and 
continuous spark -- in a rarified atmosphere), and solid-state lights (LEDs).
----- snip 8< -----

I left out LEDs in my last post! For the sake of completeness I wrote this 
part anyway:

LEDs are solid-state emitters that operate on an atomic level, except for 
the white LEDs which are currently phosphor-based like fluorescent lights 
(they use a blue (silicon carbide) LED to light a phosphor that then adds 
in some other wavelengths to give a white light). There are some new white 
LEDs being working on that don't use a phosphor, but not too many are 
commercially available yet. LEDs are very efficient, and last a *very* long 
time, but are not currently of much use for general aquarium lighting due 
to the high cost to build a fixture sufficient to light a mid- to 
large-size tank. Eventually we should see more economical LED-based 
aquarium lights, but that is probably several years away yet.

     -Bill


*****************************
Waveform Technology
UNIX Systems Administrator

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