EDIT: Cleaned eheim, drone from head

[alex182]

EDIT: all air is out now
but there is a slight mechanical drone from the head. Impeller?
sounds like one of those really cheap air pumps.
Did i put together the impeller wrong? The impeller isnt worn out.
Any idea what could be causing this?

[swampy1972]

The easiest place to start would be to take off the pump head, remove the impeller and give the housing a good clean out with a cotton tip. Also give the impeller and shaft a good wipe down and check for any little burs/damage on the impeller blades.
Sometimes you can get a film of waste build up in the impeller housing that causes it..