Well it has been 2 1/2 weeks since I started using the skimmer and after a break in period that seems to be just about ended I decided to empty the collection cup that was half full. It has been about 1 week since I emptied it last. The water was the color of strong tea and the tube was coated with a thick layer of sludge. I made one mistake while emptying the cup .... I smelled it. Almost returned lunch. Very happy with the performance considering it is running on a 85 gallon system with now 5 small fish. I will definitely not be smelling the skimmate since it now pretty well broken in.;D In my limited experience with skimmers this one is awesome, with far greater effectiveness and I paid about the same as I paid for my CPR Bak Pak that was used on my 26BF with a much heavier bioload to less effect.