So I've had my tank for about 1 month and a half and I'm not sure if if I'm supposed to change the cartridge completely or not. I've seen multiple websites where some say change the cartridge because it runs out of carbon, but others that say never change it because you will lose beneficial bacteria? I'm concerned about if I'm doing this horribly wrong and should have changed it by now so I hope I can get some more information on this. Also I have a 10 gallon tank with a pretty friendly betta and 2 guppies. The filter came from the 10 gallon top fin aquarium starter kit.