personally I would buy a new bio-wheel. As far as cleaning a good course brush that has been used on anything else (get at local store like petco,petsmart)and I can't stress this enough DON'T USE SOAP OR ANY CLEANING AGENT!!! I would also get rid of the filters and clean the filter system. If your going to use anything that this gentleman has given to you with the tank, such as fake plants and decor I would dip those in some boiling water (Note the word Dip!) If you let them set in the hot water it will disfigure them. I have bought 2 tanks used and so far I am doing OK :lol: My tropical tank has been up and going for about 2 years and the cichlid tank is just getting started
Wash them out with a brush for that tank (yes I have one for each tank, never mixed them) and bought new filter systems.
Hope this helps
if not maybe some else can give you a better answer :thumb:
Hope this helps