cycling a new tank with old media

  1. nat72sherman Initiate Member

    I'm upgrading to a new 30gallon tank. Currently I have a 20L. I'm transferring the fishes which are 2 small angels, HOB filter and 2 live plants only. I will be adding a used cannister filter as well. So am I still looking for all the signs of a cycling. Spike in ammonia, nitrite, then nitrate?
     
  2. Lexi03 Well Known Member Member

    If your current tank is cycled, and you plan on leaving both filters on, you would watch for any rises in ammonia and nitrite just incase, but you should get an instant cycle. I would test daily for 1 week if you don't see any ammonia or nitrite spikes by then you are set.
     

  3. nat72sherman Initiate Member

    cool thanks
     
  4. Wendy Lubianetsky Well Known Member Member

    That is not really cycling a tank, that is more like just changing the container.:;hi2
     

  5. jbdub Member Member

    I did this recently and it worked fine but I moved my fish over slowly over a 10 day period. Checked water quality and fish behaviour every day and it all went well. Couple months later and everyone is fine :)
    In actual fact the glowlight tetras started breeding like crazy as they were the first ones in and had the place to themselves!
     
  6. bowcrazy Well Known Member Member

    As others have stated if your present tank is cycled and you use that filter in the new tank and don’t increase the bio-load by adding any new fish right away your tank should be instantly cycled. This is not to say you shouldn’t test it for a rise in ammonia or nitrites. I would recommend testing it at least twice a week for the next month and I would do at least a 25% water change once a week. If you don’t observe any problems over the next month I would say you are safe to start adding to your stocking list.
     
  7. LyndaB Fishlore Legend Member

    +1

    I've always been instantly cycled when using this method. You are seriously increasing your water volume between these two tanks, though, so should be diligent in testing.