Every workshop I do, means my tripod often gets dumped into salty water. Salt water is highly corrosive, and if you're doing a lot of beach shooting, you should be stripping down and cleaning that tripod of yours after each outing. One of my clients from the USA, Mihir, sent me this link today -
Really Right Stuff have a short tutorial on how to dismantle, clean and re assemble a modern gitzo tripod. I've just run through it and it's pretty good advice. You may find sometimes, that you do need to use some grease on the threaded collars though - if you do - a word of advice - get the Gitzo grease. I've found others are not suitable and once mixed with salty water, can lend your tripod frozen up for good.