Clearing an airlock from the Filter.
If your equipment is making an unusual noise (this can sound like a loud rattle) then it is likely that some air has made it's way in to the Filter. It's important to clear this as soon as possible in order that the Filter can resume functioning correctly. If the Filter is left uncleared the creatures in the tank are not receiving clean water which can ultimately lead to loss but a long time airlock can also damage the equipment.
