For my fluval 305 how offten should i change my media inside Thanks
Short answer, you don't.
When you do filter maintenance just give the media a swish and rinse in tank water to wash away and crud and nastiness and then put it back.
The sponges should only need replacing if they are literally falling apart or so clogged they can't be rinsed clean.
All of this stuff, particularly the bio media, house the vast majority of your tanks beneficial bacteria. If you change it all you are doing is replacing this colonized media with barren media that will take time to be colonized with bacteria and be of any benefit.
+1 to Lupinus
If you do have carbon, then you need to change monthly.
Other than that, your mech and bio media never need to be changed. Unless, as Lupinus said, they are in VERY bad conditions.
True about the carbon, always forget about that lol.
Dont use carbon and problem solved. Or place in mesh bag for easy removal.
Yea, you could just not use carbon at all. I don't use carbon.
100% agree with the above.
The only thing that gets changed in my canister is the fine filter pad (water polishing pad), I probably replace it once every 8 weeks or so.
I do a rinse of the other media in old aquarium water when I change the fine pad.
is teh carbon the black stuff lol?
Yep. Carbon, aka Activated Carbon and Charcoal.
Separate names with a comma.