Hi everyone, I am setting up a new tank. I have never set up a tank before without cycling from scratch, but as it is my 3rd tank I have been able to put filter media from another (cycled) tank into the filter. It has now been 3 days and the ammonia has been 0 even though I have been putting fish food in. The tank is currently empty except for gravel. How do I know when I can put fish in? How do I know if putting the old media in actually worked and helped to cycle the tank?