About changing filter media..
Just something i was wondering, how do you replace filter media in your tank?
I assume if the filter houses several spounges you just replace them one by one, allowing bacteria to accumulate on the new one, then change the next..and so on. But what if the filter only has one sponge? surely you cant just whip it out and replace it with a brand new one?
How oftern would you recommend replacing the media?
Also, what happens if you dont replace it? What are the effects on the tank?