Of course the nh and no2 spiked. Bacteria needs time to find a place to culture. However, in my 90G, the spike did not last nearly as long as without. The trick is first adding ammonia until you get high readings, and then adding the bacteria. It takes a couple of days, then you will see the ammonia levels coming down very quickly. I prefer to add it otherwise it will take a lot longer for bacteria to culture from scratch. Of course since I now have 3 established tanks, I can take bacteria cultures from them.