According to Dr. Tims, when following his process and when nitrites get to high the cycle can stall. He says to do a 35 to 50% water change. All my ammonia went to 0 in my qt tank but I had supper high nitrites. I did a 50% watcher change dropped the nitrites down under 5ppm. I waited a week and they didn't move. I did another 50% and brought it down to around 2ppm and it's been another week and it hasn't moved on its own. Should I add more bacteria and wait or add more bacteria and do another large water change?