Media Bacteria

Now, don't fall over...but I am actually posting a fish related question.

Stoopid Question No. 672:
If I bought some filter sponge and put it in my tank, maybe near my filter, and kept it there until I needed it, would it give me a decent head start in a new filter in my new tank when it comes?
I will have to get a new tank up and running before I could transfer all my little fishy friends over to it, so I won't be able to pinch enough stuff out of my current filter as I don't want my current tank to experience problems. Does that make sense?
All thoughts welcome....I think

The problem is that you would end up with exactly the same number of bacteria spread between the original media and the new. It's the amount of ammonia that determines the number of bacteria, not the amount of media. So when you took the new media out, it would have the same effect as removing some of the current media. And bacteria would only grow very slowly in the new as they need a good water flow through the media to grow in any significant numbers.


When you get your new tank, do you intend moving all the fish into it or leaving some in the current tank? Will you be able to set up the new tank (albeit without any filter bacteria) while the current one is still running?
A couple of weeks ago I transferred everything from my 125 litre to my new 180 litre, but as I didn't want the old tank I moved everything, fish, filter, decor, water. If you intend leaving some fish in the current tank, you just need to divide the current media between tanks.
Or take a small bit of current media and do a fishless cycle. You can remove a quarter of the current media with no problems. Since it's getting the bacteria started that the long bit, even a tiny amount of media can significantly reduce cycling time.