Hello, I have had a 5 gallon tank set up for almost half a year, but have never changed the filter cartridge during this time. I was told that its not necessary to change unless its literally falling apart, and that advise has proved fine so far. But now the time has come to change it, but I don't know how to go about it without messing up the colonies of beneficial bacteria that live on the cartridge. My filter is just a simple one with a one piece cartridge, I think its called a tetra whisper internal filter. I can open a thickish bag, and all thats inside is some carbon. How would I take this one out, and put in a new one, without stalling the nitrogen cycle? I was thinking maybe to take out the plastic brace, so it becomes just a media bag filled with charcoal, then cut it in half at the seams, and put half of it into the new cartridge in the same tank, and half in my power filter in a 20 gallon tank i'm cycling, to seed it. Would this work? Thanks in advance for any advice!