For the past 10 days or so, I have been treating my betta for finrot with melafix. On the bottle it says to remove any carbon from the filter, so I removed my filter media. I use Right Size Z cartridge for my eclipse tank. My question is, is it harmful to my fish for removing the whole filter cartridge? Doesn't it take away my bacteria? Also, on the package it says to replace the cartridges every 2-4 weeks so wouldn't that also remove my bacteria? Sorry for all the quesitons!