Best way to seed a new filter with bacteria?

[LionCalie]

I'm currently in the process of dividing a newly purchased 10 gallon Top Fin Kit. Just waiting for the sealant to sit 24 hours before I fill it up with water. I'm wondering what is the easiest/quickest way seed the new filter with bacteria?

It needs to be quick because I took in two rescues needing a home. One of the boys is in a breeding box in my established 20 gallon and I would like to take him out at the soonest possibility. I worry about it stressing him out, although he doesn't seem bothered. He's very calm and friendly, doesn't flare at all. He would be a great candidate for sharing a tank with other suitable fish, which I'm keeping in mind if I decide to adopt him out.

Anyway, so I'm wondering if putting this new filter in the established 20 gallon along with the current filter would be a good idea? Or would this still cause spikes and thus be dangerous? I'm confused if the established filter will keep everything stable or not. I've got extra filter floss that I put in the established filter a few days ago, which I will be putting in the new one.

Thanks in advance for any help, I know this all probably a bit confusing.

[PitGurl]

The best thing for you to do is to take the filter out of your 20 gallon and swish around in a bucket with some water from your new tank. Then pour the water though some filter floss or something fine to catch any big particles. Add filterd water to your new tank. It will be dirty looking but that is good. Make sure your 20 gallon is healthy!

[LittleBettaFish]

You can just take some of the media out of your established filter and put it into the new filter. Then just move some of the new media out into your old filter to make up for the surface area and beneficial bacteria you've removed.

I do it all the time using media from my goldfish tank and it works a charm.

There is usually a slight period of adjustment for the new filter so just don't assume it will instantly cycle your tank. You may still have to do a few more water changes than usual until it establishes itself.