I use public water, but I have mixed it and let it sit a little, then tested it, 0. I did buy RO water but did not see it come down then either. I just tested all of the other parameters and they are perfect, just the nitrates are either 5 or 10, can't reaslly see a difference on the chart so not quite sure which it is. Not sure what you mean by aeriating the water.
Not sure how much rock I have, the tank was given to me with several peices of rock, and I have bought more since I have had it. I am sure it could use more though.
In the process, natural world, of going from nitrites, ammonia, and nitrates, are the nitrates supposed to go down on their own? I know we do water changes to help off set them, but is the bacteria actually supposed to help with this?
Shelley