I bought a tank off of CL and i love it, it came with a Berlin Protein skimmer. I have had it set up for almost a year and my tank is doing great, however i have never changed the skimmer cup. I looked at the skimmer and noticed that the bubbles inside of the chamber appear to be a small tornado like colum. Is this normal? i took it apart yesterday and clean everything out, but its still just a small tornado, shouldnt the chamber be full of bubbles? Any help would be great, i dont want to spend the money on a new one, but it doesnt seem to be doing its job. Sorry no pictures