Re: Heating Pads

> From: Erik Olson <olson at phys_washington.edu>
> Date: Sun, 23 Apr 1995 18:46:36 -0700 (PDT)
> Subject: Heating Pads
> Substrate Heating Cables
> contributed by George Booth
> UGF will provide warmth for biochemical activity, and nutrient and toxin
> transport. Hot feet would be very tricky to achieve, if not impossible.
> Detritus pulled into the gravel can be chelated by the substrate, but a
> reducing environment is almost impossible unless a very slow flow is used
> and that would be hard to do evenly across the whole substrate. 

	Others have reported that UGFs inhibit plant growth.  My own experience
seems to agree.  Given George's comments here that a UGF would provide nutrient
& toxin transport, chelation and substrate warmth, I'd suspect these are the
_minor_ effects here (if they were the major effects, then UGF would be better
then non-UGF, no?).
	This leaves the other effect(s?) of substrate heating as more important,
namely the reducing environment.  I'd expect an unheated plain gravel substrate
to provide this better than anything with circulation.  This would also suggest
that a heating-pad aproach might be better than the heating cables as it would
provide heat evenly enough to prevent circulation.
	I know my unheated gravel substrate seems to be better than the UGF
substrates I used to use.

	My observations certainly are not scientific in any way, so does
anyone else have observations that are more scientific.. or how about just some
equally unscientific observations that dispute this? :-)