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Sun Tubes


  1. Natural lighting
    by Jeff Dietsch <dietsch/> (Thu, 22 Oct 1998)
  2. light tubes
    by "Hutton, Don" <DHutton/> (Thu, 22 Oct 1998)
  3. Sunlight
    by Dave Gomberg <gomberg/> (Thu, 22 Oct 1998)

Natural lighting

by Jeff Dietsch <dietsch/>
Date: Thu, 22 Oct 1998

   George wrote about natural lighting and contemplates the benefits of
it's uses.  Someone else beat me to it, but I have been thinking of the sun
tube approach myself.  I would think that natural sunlight would be much
better then any artificial lighting.  I like Kens idea that is may be
similar in cost to an artificial lighting fixture, and then there would be
very little retubing costs.  I would think though that supplemental
lighting would be nice for late evening viewing.  Obviously this is not
something everyone is going to do, but I really like the sun tube concept.
It would offer a way to collect and deliver light into interior rooms and
more importantly then a window you can direct it to be from directly
overhead and maybe even come up with a good way to "throttle" it.  
    Your right all the PAR, LUX, lumen degradation etc etc etc goes out the
window.  I also wonder about the effect of the non visible radiation on
plants and more importantly fish.  Look at all the stuff the Herp community
found.  Hell fish are almost lizards:)  The only potential downfall I see
heat.  Windows or tubes, I think heating may become an issue.  
    I do not really see any big advantage of the daily variation and change
in light and position relative to the plants.  Animals though may enjoy
that more.  I would also think that seasonal variation would have less of
an effect.  I think that most of the plants we grow and closer to tropical
regions, and the closer they get the less of a light season there is.  In
fact the further north we try this may be a little more detrimental to the
plants in the winter months.  Well especially if you live in Nome Alaska:)
For our plants Seasons are probably more defined by water levels and all
the water parameter issues that go along with that.  

    Well that's getting off topic.  If anyone has used light tubes for
tanks of not?  Are they simply aluminized mylar tubes?  


light tubes

by "Hutton, Don" <DHutton/>
Date: Thu, 22 Oct 1998

I recall a fairly lengthy discussion of solar tubes on Compuserve.
Richard Harker (if I remember correctly) who has done considerable
testing on the PAR outputs of MH lighting found that solar tubes
provided disappointing levels of PAR.  His conclusion was that they
would not be an adequate source of light for reef tanks.

If anyone's interested I'll see if I can dig up his data or send him an



by Dave Gomberg <gomberg/>
Date: Thu, 22 Oct 1998

At 03:48 AM 10/22/98 -0400, Ken Potter wrote:" 
> I plan to build a large tank (300
>gal ?) for this room and would like to take advantage of the natural light.

At the risk of going high tech on you Ken, look into a heliostat.  It is
basically a mirror on a 1 rpd (revolution per day) motor.  Since it follow
the sun across the sky, and since it reflects the sun in a line due south
and parallel to the ground, the beam is always in the same place.  Now you
can move it where you want with more fixed mirrors.  You can get very high
quality mirrors in K-mart or wherever.   They are made from PPG float glass
and my last one cost $1 for 1x4'.  By investing $50 in a motor and drive
and $50 in a mount and $50 in mirrors you would have something better that
any commercial device and at a lower cost (and simpler).  

- --
Dave Gomberg, San Francisco  

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