What Is A Biological Filter?

[GeordieFishLover]

Do you buy one of these?
Cheers lol I'm confused.

 

[OldMan47]

There is no biological filter that you can just buy. What you can buy is an aquarium filter made by any of a large number of manufacturers. Those filters, whether simple sponge filters or fancy canister filters, are just a piece of hardware that has the potential to become a biological filter.

Each of us needs to establish our own biological filter. You do that by performing a fishless or fish-in cycle on your filter. When that is finished, the hardware that you bought with your tank, thinking it was a filter, has become a biological filter. The biological filter is the name we give to mature bacterial colonies living on surfaces in your tank. Many of those bacteria are living in your filter and moving that filter to a new tank will mean that tank then has a biological filter on it.

 

[Rooster]

Do you buy one of these?
Cheers lol I'm confused.

A mechanical filter, removes particles MECHANICALLY, ie traps them in some sort of "media" like sponge etc..... so all it does is clean the water.
All decaying matter releases chemicals into the water, and fish waste does the same.... chemicals that NEED to be removed (would you like to live in your toilet ?)
So , enter the BIO filter.... its the SAME mechanical filter, only nature lends a hand.... wherever these "nasty" chemicals exist, bacteria will setup home... this is the "cycle" mentioned so often on the forums, its simply a matter of time before this happens.
Once the "good" bacteria become established, then you have a bio-filter !

Some more advanced systems exploit certain traits of bacterial growth to maximise the colony, but most of us settle for a bog standard filter, and let nature (with a little help) do the rest.