How to tell if you're overskimming?

[DiverDude]

Originally Posted by Slick Fork

I've always been under the impression that overskimming is a real hazard, trace elements are easily replaced but I would be concerned about the microscopic life that gets removed through the skimmer

I'm no expert but I'd have thought that the microscopic elements would be the FIRST things to be stripped out by skimming and the heavier stuff stayed behind and would only be removed by excessive skimming....