Aquatrance Octopuss Reef Skimmer Filling with Water

Ok so, my protein skimmer cup constantly fills with water, sometimes overflowing. I have taken it a part, piece by piece, and it still has this problem. Has anyone else experienced this or know why this is happening? The skimmer is just a little over a year old.



ps. I don't know how to have the images rotate, so I'm sorry it's sideways :(