Noisy Aquaone Cf-1000 Canister Filter

[chemflex]

All I can hear is the constant movement of the bio balls in my CF1000 filter. Is this normal? - surely not! If there anything I can do to stop it?

 

[ox5477]

You can hear them moving around cause there is prob free space in there. Either buy some more bio-balls or some other media to fill up the cansiter and it will stop everything moving around and the noisy should disappear