Re: UV-B, Anthocyanins and high kelvin bulbs

["Daniel Larsson" <defdac at hotmail_com>]

Initially I had 4 GroLux (3000 K?) and 2 Biolux 
(7200 K) bulbs (newly bought a couple of months
ago). The L. arcuata was completely
green. I didn't want to induce nitrogen deficiency.

I tried using a Hagen Reptiglo 5.0 (UV-A, UV-B) 40 watts 
for a couple of weeks (without cover glass!) and my 
L. arcuata and P. palustris changed color in a matter of 
days. Dark and deep red, almost black. Unfortunately my
Fe-level dropped rapidly with UV.
The UV-bulb oxidized the nutrients in the water column.

A week ago I bought a Philips Aquarelle 10000 K as
replacement of the UV-bulb and the new shoots of the 
L. arcuata is turning from green to the kind of red as 
seen in, for example, Aqua Journal.

So my experience is that anthocyanin is one kind of red
that is easy to induce with UV-B, but the kind of red
that one really wants will be induced by high kelvin bulbs
and adequate nutrient levels.

(The "right" red color is also induced by my other
low kelvin bulbs - at max depth of 20 cm. I guess
the "blue" light from the high kelvin bulb has more 
energy and reaches deeper down and therefore
manages to induce red colors at deeper depths)

// Daniel Larsson
http://www.akvarie.net/defdac/