actually, it appears that i will have to take the skimmer out to clean it. and btw, i have seen a lot of "better skimmers" in 18 years of working at the same marine only aquarium shop , and this one that is going to sell for a tad bit over 200 dollars inc pump performs just as well as skimmers that cost twice as much. what you see in that cup is after 2 days, i have already cleaned it 2 more times since those pics were taken, and it will probably be due for another cleaning tomorrow.sure maybe a euro reef may perform a bit better, but then again you expect a 400 dollar skimmer to do that. i have had quite a few skimmers in my time.(ets,emperor aquatics,kent marine,aqua medic,top fathom,mtc,berlin,the terminator when it was an air driven skimmer,amiracle,excalibur,big mombasa, the over priced oceanic skimmer,). these are skimmers that i have personally tried or owned(i am sure i have forgotten a few)believe me, the crud is collecting on the walls AND in the cup, and it has not even been on the tank a week.