Re: Re: Lighting and Lux

[Brown_D at pcfnotes1_wustl.edu]

To compare different lamps and light output to plants in different tank
setups, I'd think it would be useful to have two parameters:  lumens or lux
or whichever light quantitation units are most appropriate at varied
distances from the lamp in air, and then how that decreases once the light
enters the water.  That way, you could calculate how much light bulb "x"
gives when 2 inches above the water surface of a tank with 12 inches of
water in it, and compare that to bulb "y"  held 1 inch above a 19 inch deep
water column, to see if x and y are comparable setups.

(Of course, that's still only dealing with the single dimesion of depth,
and doesn't take into account the surface areas and how the light intensity
disperses over the area of the tank, or the photosynthetically available
fraction of the light, but it might be more useful than watts/gallon
alone.)


Diane Brown