How often do I need to change the filter media in my aquarium?

Question

I have a 30 gal. tank with a TopFin 60 runnning dual mechanical/carbon filter cartridges as well as dual biological sponges. How often do these need to be replaced. I understand that the carbon actually wears out pretty quickly. Do I simply replace the carbon in the mechanical filter cartridge? Or do I put together a new mech. filter cartridge with new carbon? And how often? Also I'm nervous about changing out the biological filters because I'm worried about causing a mini cycle. Please advise. Thanks.

Answer 1

Most filter cartridges and chemical filter media suggest cartridges be replaced roughly once a month (follow directions).  Some people apparently wash out their cartridges and reuse them, but I never have and my water is never cloudy.  I get all the gunk out of the filter system if it needs it and replace my filters about every two months, or when I see the water flow isn't what it should be.  Please see the link below for more instructions.

Answer 2

You don't actually need carbon in your filter unless you have medicated your tank and want to filter out the medication from the water.  So I wouldn't panic about replacing the carbon.  Although if you want carbon in your filter, you can just replace it and not the whole cartridge (as long as the cartridge comes apart).  You should do that every 3 months or so.  

The sponges should last a very long time.  If you have dual sponges, then you you should have no worries about causing a mini cycle by killing off too much beneficial bacteria.  You just squeeze out the sponges in conditioned water once a month.  That way none of the bacteria is killed off.  If you ever need to replace your sponges, replace one and then wait a month before replacing the other one.  That way you'll always have one sponge full of bacteria up and running.  That's the beauty of dual sponges.

I use DIY sponge filters and I have sponges that have been in use for years and show no signs of deterioration.

Answer 3

You shouldn't ever really have to replace the cartridge, by throwing out and replacing it you throw away all the lovely good bacteria that lives there and keeps your water parameters stable, which will cause your tank to spiral into a cycle and kill off your tank inhabitants.

You can rinse it off in old tankwater during a water change to get rid of excess gunk.

Replacing it should only be undertaken if you're restarting the tank from scratch. If you really want to replace the cartridge for whatever reason, run the new one with the old for a few weeks to allow the bacteria will colonise it, in other words, clone it.

As for the carbon, I run my tanks without it entirely. It effectively runs out of steam within a week! It is useful for removing things like medication from the water, that can also be a hindrence if you're dosing your tank.

Answer 4

once a month or something