Re: [APD] Light and Lids

["Mariano F. Bonfante" <mariano_bonfante at hotmail_com>]

When I took these measurements, first I use the tank lamp system. But my 
luxometer was sensible to incidence angle, and the pendant I used has 
intensity lobes, so the real absorption value with different glass angles 
was uncertain.

So I switch to sunlight. In this case the measure was more stable, showing 
no difference with the luxometer lens perpendicular to the sunbeam, and the 
glass taking from ?30 to +30 degrees from the perpendicular. The same 11% 
showed up, relatively constant with the glass angle.  (measurement error has 
to be calculated).

So I decided to remove the glass hood, despite more evaporation. But more 
efficiency was achieve, and also I can made some enhancements like placing 
an Aglaonema Simplex emerged, with its roots underwater. In this condition 
this plant is doing great.

Mariano



>From: Jerry Baker <jerry at bakerweb_biz>
>Reply-To: aquatic plants digest <aquatic-plants at actwin_com>
>To: aquatic plants digest <aquatic-plants at actwin_com>
>Subject: Re: [APD] Light and Lids
>Date: Tue, 20 Sep 2005 08:08:43 -0700
>
>Mariano F. Bonfante wrote:
> > With a luxometer I messured 11% loss. The same value was obtenied with 3 
>mm
> > to 6 mm glass.
>
>I do believe that nearly all of the loss with glass occurs due to
>reflection at the physical boundaries (i.e., the interface between air
>and glass). No matter how thick the glass is within a normal range found
>on an aquarium, the loss will be the same. I always understood that
>about 7% was lost at each surface with normal uncoated glass. Seems like
>if that was the case, a lid would be predicted to lose about 13.5%, but
>that's not far out from what you measured.
>
>--
>Jerry Baker
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>Aquatic-Plants at actwin_com
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