I have heard skimming wet will lower your salinity, but I'm not 100% convinced it does. Skimming wet will remove more water from your system, yes. And the water it removes is salt water. But unless you are taking out cups and cups per day, (or have a really small system) that amount should not make a huge difference IMO (unless of course you have gone long periods between doing water changes). The only way to be sure is to test the salinity of your skimmate. If it's much higher then your tank, then that very well may be your culprate.

Per your clown question, i've read that when adding a new clown with an existing one, the new one should always be much smaller then the existing one. But, that is from reading, not personal experience, so milage may vary. :-)