I set up Stevefish's tank as a natural planted tank. A layer of soil, a layer of sand. Note: He has yet to spend time in the tank, besides when I VERY FIRST set it up. He's been quarantined until I know it's stable
(and because I rescued him from persistent horrible water quality and wanted him in pristine water for a while).
This past weekend, I basically tore the whole thing down because I wanted to add more plants and rearrange (final time, of course). I noticed while in the process that TONS of air had collected under the soil. It smelled BAD.
I came home again this weekend and noticed that once again, there's air under the soil. I had figured it was because I didn't have enough plants the first time (which I didn't - I was in a hurry when I set it up... a mistake, in retrospect). When I push down, air bubbles come out of any hole they can find. Not as bad as the first time, though.
Is this... bad? Normal? I can't find anything anywhere online about it.
Note: There's a snail in the tank. Ammonia and nitrite are 0 ppm, so the plants are in fact doing their job.