Thanks VJM! Here is some more relevant information:
My amazon was growing, it sprouted a new vine and everything. My wisteria was completely black at the roots and fell apart when I did a water change.
There is a HUGE number of snails in my tank, and they produce a lot of waste in a short period of time. The waste produces ammonia. I did research this before I got them. There are probably thirty or so, not including the mystery snails. And those are just the ones that I CAN see...
There haven't really been any 'spikes' of ammonia. It's stayed constant, steadily rising until I do water changes. I realize that I do need another plant to replace the wisteria.
If my BB has been killed, what should I do differently this time to make sure the cycle works okay?
Is there any other way to be sure my cycle has restarted?