Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
There is no real point to trying to cycle the new media in such a short time.
Just rinse as needed. If you want to add some bacteria, you can, but it would not get growing much just overnight, and whatever attachment had started would get broken loose when you move the substrate in setting up the new tank.
Get a bottle that includes Nitrospiros species of bacteria.
Save all the bacteria you can from the old set up.
Filter media will have the most bacteria. Save all you can of this. If it fits in the new filter, great. If not, then put it in a mesh bag or nylon stocking. Hang these bags inside the tank in the new set up. Then, about once a week, remove one bag.
The uppermost layer of substrate will also have a lot. Skim the top 1/4" to 1/2" and put this in a mesh bag or nylon stocking, and do the same as with the filter media.
There will also be a pretty good population of bacteria on all other surfaces like driftwood, rocks, plant leaves and stems...
These bacteria do not need to stay under water. They can be kept in a humid location, with plenty of oxygen. For example keep the rocks and driftwood damp in a garbage bag or in a bucket while you are doing the change over.
The filter media can stay in the filter, as long as there is a source of oxygen. About an hour is no problem. Longer than that I would take out the media and put it in a bucket with just a little water. That way the bacteria get oxygen from the air, but the filter media will stay damp.