Filter bag and charcoal

[myriam]

I have a TopFin 20 I got with my 20G kit three months ago. I haven't changed the bag yet, but I've changed the charcoal once. I'm worried if I chuck the bag and put in a totally new one, something weird will happen with my tank and the good bacteria.

1. Should I change the bag? Or just wash it and replace the charcoal?
2. How often should I change the bag?
3. Are you supposed to pre-treat the new bag in any way before using it?

 

[Allivymar]

You can rinse the old bag in some tank water (the stuff you take out during a water change). Shouldn't cause any probs. I change mine when its starts clogging up; when the water seems to roll over it instead of going thru it. Can be anywhere from 2 weeks to 2 months on the average; much longer if you use filter sponge instead of the filter floss media. Nothing needed to do to a new filter except rinse it out. You could squeeze some of the stuff from the old filter into the new filter after rinsing it if you're worried about losing too much bacteria.

 

[myriam]

What about the carbon? I have the Ammo-Lock stuff, with a mix of black charcoal and white pellets that supposedly suck up the ammonia.

Thanks