@Lennie, if you have two sponges, you can just move one over to your new tank.
And @TheBlueBeetle, if both your sponges and rings have bacteria, isn't cleaning the sponges out with pressurized water similar to boiling half your biorings?
@TOtrees here is one of the videos I found during my research into bimedia. In it a study is discussed where scientists measured the amount of bacteria found in each media type and found it liked fine sponge best, and course sponge second best tied with ceramic. Therefore, the statement that "bacteria prefers sponge over all bimedia is just rubbish" is in and of itself, rubbish