- Reaction score
- 1 year
Hi everyone, I was wondering what an undergravel filter does exactly and what i need to do to make it run smoothly? i got my hands on one for free from a friend and have set it up in my 20 gallon tank, but does it need any filter media? how does it work? i’ve got it in the tank & attached the air pump to the tube things and that’s it. sorry if this is ignorant lol but i have no clue how i should manage it at all.