This question may have come up before and it might be buried in here somewhere but thought this might be easier, I've been seeing a lot about "bio" filters is running one of these better than the old carbon filters or are they about the same?
What filter have you got or planning to get??Where would I get filter sponges? What do they look like?
I'm assuming that this is one of the MarineLand series of HOB filters that use cartridges. You can use ceramic media (ceramic rings specifically) in the vertical space next to the cartridge by running a length of fishing line through the ceramic rings (think necklace). This would allow you to easily add and remove the ceramic rings during filter maintenance.I have the bio wheel for a 10 gallon