I too have heard that water-absorbant jells may promote fungus growth. I
have not heard about toxic effects, but the chemical that they are made of
is similar to a chemical which is toxic to humans (and much used for electro-
phoretic jell-rigs). Somehow the name of the stuff escapes me.
I knew a guy in Connecticut who grew Nepenthes under metal halide, or a
similar light source. The thing was big, hot, heavy, and undoubtely
expensive to buy and run. i did not like the looks of the yellowish light,
and neither did his nepenthes. Nevertheless, the plants grew, and the heat
was a benifit in a cold Connecticut basement. It threw a lot of light, but
the largbe circular area of irradiance was a lot harder to work with than a
linear tube-lit area. I'd say forget halides and stick with flourescents.
MJC