just so you know i have been messing with the decor a bit. i am getting a bunch of new plants in next week. i will be adding a bunch to my tank and my daughter's tank. in hopes that i can get her tank up and running again. i had to change the filter on her tank because it kicked out on me. though i kept the bio filter part and wedged it into my new one. so that way i didn't have to recycle the tank. didn't want to put anymore stress on the poor fishies...though that seems mute now. how long should i leave that old bio filter part in?