Re: Substrates - charcoal/carbon

From Stephen Pushak:
> There was no comment yet on the use of charcoal which
>was recommended in the TFH book. This may be a very worthy suggestion too.

I meant to comment on this earlier, when it was first mentioned on APD. I
have been thinking about this for some time.  Carbon/charcoal is frequently
suggested in books/articles about house plants or terrariums. It is supposed
to keep the soil "sweet."  Presumably, by absorbing released gases (like
H2S?). If sweet is good, then sour is bad. Sour could mean foul, i.e.
anaerobic. So, could carbon/charcoal do the same underwater? Since these
materials are light and porous, could they also help keep substrate
permeable; they are absorbants - what about CEC potential? Will they
adsorb/desorb or just absorb? I remember reading in a new aquarium book -
The Complete Aquarium - that crushed coal could be used for a substrate to
create a desired look. I wondered about its affect on tank chemistry and
growing plants. Maybe has potential 
advantages! Ah, yet another tank to set up :-)