I have been hanging out with the goldfish people on another group (I
have one goldfish tank) and they are always talking about using sand
or no substrate at all to get rid of all that messy stuff on the
bottom of the tank. Having read that good bacteria live in the
substrate I got to thinking about whether in general that crud is
really good or bad, specially in a planted tank. Is it just "soil in
the making"? Or is it "nasty pollution"? I must admit it looks
horrible when I vacuum the gravel, specially when I come across a bit
of food that has fallen down between the gravel where the fish can't
get it and has gone moldy.

On the other hand, I have had a small plastic tank going since last
summer with no filtration or maintenace whatsoever that has pond
water, snails, plants and lots of tiny pond creatures. Obviously some
kind of balance has been worked out there. The snails make lots of
dropping but maybe the plants and tiny creatures use them as food?

I'd love to hear what you knowledgeable people think. I've only been
keeping fish for less than a year.

Judy
http://jumaka.com/aquarium