hi my new aquarium finished cycling 4 weeks ago. my fish have been in the tank for 4 weeks, is it safe for me to change my filter cartridge. the filter i have is a regent aquat tech. i just do not want to change it and then the tank loses all its bactaria and has to recycle and kill my fish> please advise thanks.
the cartridge has been in use for about 8 weeks now
the cartridge has been in use for about 8 weeks now