it works very good.I am very happy with it.It produces a steady nog.I never get the skimmer going nuts when I do a water change or over feed.It skims very steady.I always had problems with my other skimmers overflowing when I would shut the power off and then turn it back on,water changes,things like that.I have it skimming a bit wet but not very wet.I find when using the wet neck option the top of the skimmer neck stays cleaner.You still get some crud but no where near what it gets without the wet neck on,so I do see that it works.When you say the chamber do you mean from the flange to the top of the skimmer (where tho foam falls over)?Thats about 11 1/2"