For some reason, my brand new eheim 2213 is humming. It isn't like when air goes through the pump, is a drone. There is no air in it, and ive already taken it apart a few times. Is it because my came with a canister for the media that goes inside the outer canister? I have heard of people using just latice screens and having no issues, but mine didn't come with those. This is a brand new filter. Thanks