I have read the book and tried it with a 37 gallon tank, dirt didn't do it
for me, it smelled and I had troubles, I did a total breakdown and used peat
instead under the gravel with quilting batting over the peat then the
gravel, everything else I followed and seems great now I also have a 46 bow
set up the same way. For plants I have amazon sword, java moss, 2 types of
hygrophielia, sags, oinion plants, moneywort, red lugwiga, water wisteria,
Valis, bulbs of some plants in the water lilly family, willow moss, bacopa
all seem to be doing fine I have to trim once a week.

Kay