Substrates (not again!)

Elizabeth Worobell's post about really needing an anaerobic layer in the
substrate got me to thinking about changing my tank and I thought about what I
had now that I didn't want to lose.   The main thing is the huge biological
filter that my ugf now represents.  

Now I need to take you back about 20 years to early ugf days.  In those days
there were two kinds of ugfs:  The kind we have today with raised plastic
plates (plenums) that mostly or completely cover the bottom and ANOTHER KIND,
made up of a manifold of plastic tubes connected to an air-powered riser.  The
plastic tubes were perforated, sort of like drain pipe, and formed a grill or
grid that went many places on the bottom of the tank.

Now here is the idea:  What about a lower layer of some kind of organic or high
cec stuff (something on the spectrum between vermiculite and cow  manure), then
a .5" layer of coarse sand, then the second kind of ugf, then aquarium #3 over
all.  This would give you an aerobic layer on top to clean and digest any
wastes, plus an anaerobic nutrient sink lower down for the plant roots to go
mine.  Use Malaysian live bearing snails to keep the upper level relatively
free of bacterial clogging.

1.  Has anyone done this?  How did it work out?
2. Is there ANY consensus on how "organic" the organic layer should be?  Or
just opinions based on anecdotal evidence?
3. Do YOU think this will work?  Why or why not?

Thanks for the input.   Dave

Dave Gomberg, Experimenta      San Francisco CA USA   gomberg at wcf_com