Pots and Substrate Heating


I'm in the process of setting up a 90 gallon plant tank with a
Dupla 150 watt cable and a homebrew transformer-controller setup.
Thing is, I've grown quite used to the convenience of keeping
my plants in rubbermaid containers (most approx 11" * 5" * 5") in
my smaller aquariums. After all, pots & trays make redecorating
easy!  :-)

So, after rumaging through the Krib for all the substrate heating
info I could get (especially George Booth's helpful postings) it
looks like its primary benefits are:
  1) Providing warm in the substrate for "toasty roots"
  2) Providing warmth to speed up biological processes
  3) Transporting nutrients into the substrate
  4) Transporting harmful products out of the substrate.

Well, containers shouldn't interfere with the first two much since
I bury mine in the substrate to the point where tops aren't visible.
But what about 3) and 4) ?

I would think transport is primarily from convection (as opposed
to diffusion). The degree to which plant containers interfere with
convection flow would then be dependent on the what factors give
rise to the convection.

 1) If convection arises primarily because of the hot/cool bands
created by the cables, containers will probably interfere a lot. (I
will be resting the containers right on the cables so there will be
a bit of a heat band, but of course water flowing around and
under the cables won't help convection in the container).

2) If convection arises because of the heat gradient and/or
cycling of the heat gradient (as the cables turn on and off) I think
I should be ok.

Has anyone tried plant containers with heat cables ? Any

Many "Tanks",
Tim - Pittsburgh