I think that most just don't get what is meant by too large or over skimming. Do think of it in the way of it is stripping the water clean, the max a skimmer can remove is about 35% max and the very high end, of the Organics in the water. The rest just do not react to or adhere to bubble surfaces and stay in the system. Some can become food for inverts and some will die and become Phosphate and Nitrate and the rest who knows, most of it is guessing and theories. Fact, most of the crap or Organics are in the to 6 inches of the water surface or very deep towards bottom, this is why you get the great foam build up on the beaches, just look into your sump you will see how the surface of the tank ends up in the sump as you will see the slick that developes. The point I am trying to make IMO I believe the biggest contribution a Skimmer makes is Gas exchange, helps with O2 supply. There is somewhere a great article written by Danna Riddle that I read once and since can't seem to find. The title went something like "Nitrate Phosphates where did they go". In his theory which the more I think about, the more I am more inclined to believe, is in the Ocean as the water approaches a Reef and the bottom currents are pushed up from the depths against the Reef wall which when tested were full on Phosphate and Nitrate. Well what lives on this wall. Sponges and Filter feeding Fans and Filter feeding inverts ( Softies ) of all kinds, then it rolls up onto the lower Reef and it encounters more Sponges, Giant Sponges and Clams and more Fans and different types of Algae and LPS and it moves to the Reef Flat and know when the water was test has be striped of most of the Particulate matter and Phosphate and Nitrate are at almost undetectable. So as the title said " Nitrate Phosphates where did they go? " My thought and suggestion to all who worry about Skimmer size and whatever else is debated about them, just get one you take a liking to from a reliable source not Ebay $25 special. Whether its because you like the color or the build or Name or the fact it can from Germany and has a special shaft made from Minerals collected from Meteor crashes, because in the end one may have this thing and the other has this but they all do they same thing, mix air and water in a body for a certain amount of time and water is spit out on its way. The best thing it can do is add O2 to your system and the worst it can do is a: Not Foam for periods of time or b: if unit is too small and you are emptying it everyday or twice a day of dark, thick, smelly, choking, gag inducing, Wife Screaming ( what the heck is that smell ) substance. Well then it's too small/undersized. I believe the best thing to do is add a tank in replace of the sump ( large ) and fill it full of Sponges and Fans and LPS and Softies with good lighting and a nice flow in it and you will have just made the ULTIMATE FILTER.