More comments on lighting...

I'd just like to add my own $.02 to the lighting discussion:

someone wrote:

>> 2. You also have the effect of the side walls, which if clean wi
>> nearly all the light in the tank back into the water due to an e
>> called TOTAL INTERNAL REFLECTION.  A little light gets out at th
>> not much.  This means that in theory almost all the light will s
>> tank, irregardless of depth!  This only applies to the light onc
>> hit the water, so it's ideal (as the original poster said) to po
>> source so as much light as possible enters the water, i.e. close
>> surface, or for MH, focused on the surface.

to which Karen Randall replied:

>I'd like to add this to the myth list.  It may be true in an EMPTY
>tank.  It just ain't so in a planted tank.  Prove it to yourself.
> Go into the room with your aquarium at night with all other
>lights off.  Take a book with you.  You _will_ be able to read the
>book.  Where is this light coming from if it's not escaping from
>the tank?

to which I will add:


The phenomenon of total internal reflection occurs for the light which is
passing directly from the light bulbs to the inside glass surfaces of the
aquarium.  This light gets entirely reflected back into the tank - none of
it escapes the aquarium.

The reason you can read a book by the light of your (well-lit) tank is that
whatever light strikes the plants, rocks, decorations, etc. inside your
tank gets scattered randomly.  When this scattered light strikes the inside
glass surfaces of your aqaurium, it is no longer at an angle sharp enough
to provide total internal reflection.  It passes right out of your aquarium
and lights up the room.

Finally, there was also a comment about "near field" effects.  The "near
field" of any radiation is proportional to the wavelenght of that
radiation.  For visiable light, we're talking about wavelengths of 100-700
nm (1 nm = 1 billionth of a meter), so near field effects don't really
concern us if we're talking about lighting up our aquariums.

in Ann Arbor where we watched the Wolverines beat up on the Spartans with
snow flurries swirling about the Big House.