I didn't test my ammonia until yesterday so i'm not sure if I had a spike or not. Levels are good now. I know I killed all the good bacteria that was in my AC HOB. I am running a sponge filter too that has been running as long as the tank (3 months) and I figured rinsing the sponge media in the AC would be ok but guess not. I will also be adding a 2nd sponge inside the AC HOB this weekend so there will always be a back up and i will never rinse them within 2 weeks of each other.