'Reverse' quarantine

[jm1212]

if you add the filter on the ten gallon, you can also add another filter which will eventually become cycled since there is already bacteria in the tank from the old filter.

 

[Star_Rider]

the point is..you don't need to.

you have a source of bacteria (beneficial) in the existing tank.

you purchase the new tank to get more room for the existing stock.

so move the fish into the new tank with the old media, filter etc.

INSTANT cycle...you may see a tiny spike but it is only for the bacteria to catch up.

I never do long cycle with my tanks(I have 9 FW set ups) and almost an endless supply of nitrifying bacteria..it takes about 3 days to take a new tank and turn it into a cycled tank.

 

[Rbishop]

Either way will work, but I feel you are worrying for nothing.