I had planned on changing filters because I don't like the ones that came with my aquariums (too strong). Luckily I had already purchased the replacements because one of the older ones quit working tonight.
My question: Even though it's not working, should I leave the old filter in until the new one is seeded? I know when changing filters you let the old one keep running but one is kaput. I can't fit the old filter medium in the new one or I would do that.