Cycling Tank With Used Filter Do I Know It Worked?

Discussion in 'Aquarium Nitrogen Cycle' started by Han, Apr 11, 2018.

  1. Han New Member Member

    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?
  2. Briggs Well Known Member Member

    The problem with using fish food to produce ammonia is that it needs a little time to break down into ammonia. As it breaks down though, and you bacteria colony transferred successfully, it should process so quickly that not enough is going to be in the water at any one time to show up well in tests. If that's the case, the easiest way to verify your cycle is to test your nitrates which should slowly rise while ammonia and nitrite seem to stay at 0.
  3. Han New Member Member

    Thank you, that makes sense!:)