Thanks for the full tank shot! Beautiful setup and Pbass. Was the tank originally set up for saltwater? Looks that way from the return pipes on the bottom. Your ammonia spike could be from a water change. If you don't get enough dechlor in or don't get it in before the fresh water gets into the filter, the chlorine will kill the beneficial bacteria that break down the ammonia and turn it into nitrite and then to nitrate. That is probably why your nitrite reading is 0. Once the bacteria come back you may see a rise in the nitrite as part of the cycle before it gets converted to nitrate. You should change the water daily and keep testing to make sure that you keep those levels down until the cycle is complete. You don't want to stress out those awesome fish.