Is my carbon used up?

[meese-a-mew]

I need to treat my tank with maracyn but I don't know if my carbon is still doing anything and the carbon will suck up the medication. so I was wondering if there is any set time frame when carbon becomes useless.

 

[aquandrew]

carbon is unnecessary, unless you are removing chemicals. is it a filter cartridge with carbon in the middle? if so you can cut it open and take the carbon out. if you use carbon for longer than a month, it can release unwanted chemicals and cause problems