I have a 10gallon that has been used before. It kinda had some ammonia and water chemistry problems. I totally cleaned it out and rinsed the gravel rinsed the filter, you name it. I added the water and got a new betta today. So here is my question. The tank has the bio wheel filter. I changed the filter cartridge, but the actual bio wheel, I didn't change. I couldn't find a new one in the store. I rinsed it out with hot water and put it back. I was wondering if any of the bad bacteria from the old water and fish could still be stuck on there and travel into my new water with my new betta and harm him. He is just acclimating to the water now and the bio wheel is on the filter. Should I take it off in the meantime? A fast response would really be appreciated. Sorry for the novel....thanks guys!