Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
With no livestock, do the fishless cycle. You can indeed use fish flakes as a source of ammonia. It takes a few days for them to get broken down, but it sounds like the soil is adding ammonia to the system, too.
If you check the ammonia daily, and it is around 3 ppm that is a good level to grow nitrifying bacteria.
Adding some circulation would sure help. Got a little, tiny air bubbler?