I understand where you're coming from Gary. I don't have this problem, living 100 miles from the sea maybe has something to do with it, but it would drive me mad and if I had the money to throw at it I would. You might want to think about tripods with upsidedown legs, like the Benbos that have sealed legs and feet. The Manfrotto Neotec that I have is similar, but get salt water over 16in deep and it's f00ked.
I don't know of any other tripod that makes such claims about sea water and sand as this Gitzo, so that's a good start. And it's made by Gitzo who not only make the best tripods but seem to specialise in serious outdoor stuff. And I know that Andy Rouse uses them
http://www.warehouseexpress.com/Home/default.aspx?/arouse/Gitzo_GT3540LS_Review.html who is an extreme locations guy who moans about most things, but raves about the really good kit.
My problem with the one you're looking at is its size. Beautifully light for sure, but it only gets to eye level with the centre column fully up. That is death to stability, no matter what Gitzo might say. Maybe you can work around that, and TBH ultimate stability isn't always the be-all and end-all if what you primarily need is something to hold your camera in position, so long it is stable enough for the job in hand. If it was my only tripod, I wouldn't buy it for that reason, and it will still need at least a little maintenance. But unless they do something similar and bigger, you might find that is an acceptable compromise plus the benefit of the light weight. Just thinking about it now, I think I might go for it, and use IS/VR to help out if it got a bit windy/wavy/wobbly (I find it usually works very well on a tripod). Everything is a compromise somewhere along the line, ultimately.
I'm surprised you're not going for the titanium limited edition version, at twice the price
I'm sure the AA man would admire it when he picks you up in your ultra-reliable LotsOfTroubleUsuallySerious car