Can you have too much filtration. IMO no. Now the rest of the story.
No really depends on what you are trying to do and how you are doing it. As Keif has stated there is no such thing as a sterile system. Just by the fact that fish poop, there it is again Keif, and we feed our tanks there is always something in the tank that needs to be broken down. This feeds the biological filtration no matter how good your chemical and or mechanical filtration is performing. It cannot get it all out.
Those reefers trying to keep an Ultra Low Nutrient System are doing no not so that they can keep their water near sterile, but to facilitate increased feeding to their coral and fish. You will find that these folks feed heavily most more often that we do. This to enable to have the coral and fish fill themselves with available food and have the time to utilize it. In the mean time they also have chemical, mechanical and bacterial means to drive whatever is left in the water column to that ultra low condition only to start the process again at the next feeding. So do these folks have too much filtration? If that was their only goal I would say yes that they are depriving their tanks of needed food. However because of what they are trying to accomplish no they do not. They do not want the excess nutrient hanging around which would cause other problems both with unwanted algae and elevated nutrient that could in fact harm the coral. Zooxanthellae, the symbiotic algae present in coral, if left to feed on these overly abundant available nutrients will "drive the growth of the zooxanthellae to such an extent that it actually competes with the host for inorganic carbon (used in photosynthesis and skeletal deposition)" (Randy Holmes-Farley)thus actually harming the coral. This is true in calcacerous coral. NPS coral are a different story and can be discussed if so desired.
So the quick answer IMO is no you cannot have too much filtration, but that it depends on what you are ultimately trying to achieve.
