When Adding A Second Hand Filter

[goldfish]

Is this dangerous to the fish? Before I only had 2 little bubble filters in it, and I've just added an eheim 2211. I'm keeping the bubble filters in there for two weeks, to give some time for the bacteria to spread to the 2211. Should I leave the bubble filters running during this time? Or is it okay to turn them off, and just keep the sponges in the tank? Any guidance would be great

Thanks

gf

 

[Tolak]

You could either keep them running, or put the sponges from them in the new filter. I would keep them running in case you need them for a hospital/quar tank.

 

[goldfish]

Thanks!