Cut and paste..a moderator from another site......Finally, and perhaps most importantly, I wasn't referring to dissolved organics in the article being quoted, although they are certainly including in the broad sense of the statement. My point is simply that if water quality is adequate or better, any amount of skimming above that level is overskimming as it is removing substances that are beneficial to organisms in the tank - and although it continues to remove things detrimental, as well, we have already established that the water quality at that level is adequate or better than adequate. And yes, you can have water that is too low in dissolved organics. As I said, many things use it as a food source and some would die without it.
My opinion...I believe aquariums need skimmers...and I also believe it is possible to over skim. Perhaps that is why the Remora is not producing gunk in this post....not certain...but there are differing theories and opinions. I had two skimmers on a tank a few years ago...one produced some foam..the other produced little. I had better results with using one that was big enough for the tank. Again, just my opinion and based on my experience.
I'll get off the soap box...sorry for the rambling to all.