Ok, this is seriously confusing me.

I went out and bought some Bio-Spira (a 30-gallon bag, the smallest they had) and added it to my tank on Friday morning. It is now Saturday evening and I've seen absolutely no change in the ammonia levels. They're still reading over 8.0ppm.

I have no clue what could be the problem. I've vacuumed the gravel, there are no fish in the tank, no dead plants (only two small plants), and the filter with Bio-Wheel is running smoothly. I did a 50% waterchange the day before I put in the Bio-Spira.

Anyone have any clue as to what could possibly be causing this?