Home made Biological filter

[Cichlid Kid]

Thats the route i went also. I have an interal one for mechanical and an external trickle for biological.

 

[Autumnsky]

Has anyone added an air pump into the middle of the can to increase oxygen?

 

[jlk]

Thats a good idea! In my case though, its pointless because the water comes into the barrel with such force it would be self defeating. On something smaller or with less power, I think that would be a smart move!

 

[Fresh2o]

For connecting tubing/plumbing to a container I would try using a bulkhead fitting. You can find them at garden shops, home improvement, or pool supplies stores. They come in various sizes with slip or threaded ends. Basically you drill a hole in the wall of the container, put one side of the fitting in (it unscrews to 2 pieces) and thread the other piece onto the first. Most come with a rubber gasket to ensure a good seal.
You could even use them on liner material but it would work better if a piece of plexiglass or sturdy plastic was "sandwiched" next to the liner to prevent strain on the liner.