Welcome to the forum Kadar Your Leatherman is stainless but even stainless steel will rust if exposed to moist condituions long enough. The pool chemicals you are around may contribute to the problem. There are some rust preventing wipes you can use to help in extreme conditionslike thishttps://www.theruststore.com/Tuf-Cloth-P67.aspxSome will come along and say get a Swisstool as they don't rust as easily but with a little preventative care you shouldn't have a problem with your Leatherman.What model do you have ?[a wave and surge]