Don’t want to shell out the dough for pelletized carbon to keep your bacteria populations elevated? An alternative thos this media is rice. That’s right, regular old rice. The rice, like the bio pellet media, will slowly build up a film on its surface and release carbon into your aquarium to feed bacteria. Be careful though. The rice needs to be rinsed thoroughly before being used and there is a possibility that it may contain other things that are harmful to your aquarium.