hi, i have been succesfully keeping fish for 7 months now and have yet to lose a fish
i did nt have a clue how to keep fish when a friend gave me his old tank, and now i know he didnt either. although i ve learned so much in the past few months i am having problems finding info on bio balls. i got rid of my friends tank and brought a stunning new tank witch uses these in the filter box, problem is i do not know how long before i need to change any help out there 



