[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


Wright Huntley <huntley1 at home_com> wrote:

> There is *no* effective attenuation of the photosynthetically active
> spectrum in clear tanks that are less than a few *meters* deep. If you

Not quite so. I converted the curves published at
http://www.aquabotanic.com/paper2-6.html from their standard 1m depth to a
"typical" aquarium depth of 16". For pure water, absorption at the blue end
(400-500 nm) is effectively zero. But for all other cases: pure water at the
red end (600-700 nm), and water with a reasonable amount of organics, 
absorption is in the range 20-50%. Significant IMO. Of course, this should 
affect mostly low lying plants. Stem plants and large swords for instance, 
should see less of the effect.

- Ivo Busko
  Baltimore, MD