Why is my skimmer going nuts?

[dcw1sfu]

I have the Vertex 150 and its a great skimmer however can be touchy at times. If I add anything like epoxy to the system it goes nuts and will continue to overflow for days. I find the way to fix this is let it skim out what it wants by overflowing into a pale and replacing what its drained with fresh salt mix. Basically a water change via skimmer.