Thanks Sadielynn, but I've seen that too. What I mean is the typical HOB like the AC-300, Penguin, Emperor, Whisper.....you know, the common HOB's....these dont have a SURFACE Skimmer. The skilter is basically a HOB with a PROTEIN skimmer. Because with big tanks, more or less they all come with surface skimmers...or can be fitted with one. But with pico tanks or any tank from 10 below, you need all the space you can get. Wouldnt you like to have crystal clear water and no surface scum....thats what I meant.