Why is my skimmer going nuts?

[asylumdown]

It looks like that skimmer cup has a drain line on it. I'd recommend directing it out of the tank to a large bucket and keep an eye on it for a bit. It will start to drain your tank, but if there's nothing in it right now you don't need to worry too much about a mild fluctuation in salinity, and you can just add some salt to the sump as needed. If you don't have an ATO system that will replace what's lost with fresh water, you can just make up a batch of new salt water and add as necessary (though if you add something like Prime to the new water, it might just make it go nuts all over again). The bacteria won't care much about a small drop then rise in specific gravity, if one is even detectable.

Whatever is making the skimmer go nuts needs to get out of the tank. Dumping what ends up in your skimmer cup until it stops going crazy is the fastest way to the do that.