Changing tanks

[Mike1]

I just moved my 6 inch discus to a bigger tank. I am using all the same equipment as was in the old tank, filters heaters, air stones, gravel etc. I used about 2 gallons of water from the old tank. My question is do I need to reestablish a biological filter and if so how long will it take? It seems to me that this is essentially the same as doing a very large water change and there would be no detrimental effect to the bio filter. Any thoughts?

[April]

Id say yes.your right . only time a biofilter needs to play catch-up is if your adding more fish or more bioload all of a sudden. just carry on and do your wc as usual. things should be fine.
when i start a new tank i use all new water and add sponges to a new filter the night before i get the fish. i just keep 3 sponges in each aquaclear and take a sponge from each filter and start a new filter.

[Carol_Roberts]

Hi Mike:
Yes, the filter from your old tank is fully cycled, so just move it to the new tank.

April has a good idea. If you have more than two or more sponges inside your cycled filter you can remove one and add it to the new filter when you need to start a new tank.