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Posted by Greg E. on August 24, 2005, 3:06 am
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An entirely reasonable point, this was just the material I'm used to using.
Data for soda lime glass (the cheap stuff), borosilicate, alumina silicates
and other crown glasses is available, but much more of a pain to sort
through. Plus, fresnel reflection isn't a strong function of the material,
and even soda lime glass is good below 380 nm.
gse1977
> @comcast.net says...
> > You lose 6-8% of the light from the two additional interfaces. Fused
silica
> > (glass) doesn't absorb significantly at the wavelengths in question so
it's
> > just the reflections that are an issue. It's not that it's "bad," but
6-8%
> > is not completely insignificant either, especially if you are trying to
get
> > the most bang for your (electric bill) buck.
>
> Minor quibble: fused silica is an exotic synthetic material, not the same
as
> "glass". It is closely related to quartz. Primary uses are in premium
fiber optic
> cables, lenses for high power lasers, and special applications that
require
> excellent clarity deep into the UV range.
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> watts per gallon lighting and your corals. It limits the transmittance
> of the light spectrum, i hear.
>
> However, when scuba diving I routinely see photosynthetic corals in 70
> feet of water.
>
> How can 1/4" of glass wreak more havoc than 70 feet of water?
>
> Even admitting that 4-5 watts per gallon is not the same as sunlight,
> how can 1/4" of glass be worse than 70 feet of water? or even 30 feet?
>
> - fjord
>