WrenFeenix
I just got a double sponge filter as a second filter to replace the air stone in my goldfish tank. I thought it looked cool and has all the benefits of a sponge filter plus the capacity for ceramic media or carbon. Next to it is a small sponge filter for my molly fry tank.

What are your opinions on “China” filters? Would working an air stone onto this thing improve its performance?
Related question: can ceramic media harbor denitrification bacteria (bacteria that consume nitrates)? I heard it could because of the oxygen poor environment in the center of the media.

What are your opinions on “China” filters? Would working an air stone onto this thing improve its performance?
Related question: can ceramic media harbor denitrification bacteria (bacteria that consume nitrates)? I heard it could because of the oxygen poor environment in the center of the media.