soil as a substrate
i have been reading ecology of the platned aquarium (which is a great book) and i noticed that the author touted the use of normal garden or potting soil as a substrate underlayer to provide nutrients. comparing analyses in the book to the levels listed on seachem's website, pound for pound, garden soil contains more nutrients. according to the book, it also contains a source of carbon, which, in my tanks with no CO2 injection, would be a big plus. but as i read, soil has a tendency to be disruptive when first submerged. so my question is, has anybody tried using soil? what were the results? is it superior to commercially available substrates like flourite or eco-complete?
also, i have a low light tank that i started out with using bare gravel (bad idea, i know better now). the tank is a few (5) months old and i'm considering switching from bare gravel to a nutritive substrate. what are your thoughs on how to do this?