Wow, it's a only a tripod for goodness sakes. Even though it's the middle of the night, I'm tempted to wade out into the water and document the gradual destruction of the carbon fiber legs of my tripod. I really don't think it would amount to much. That's just the way I am.
The carbon fiber will not be harmed, nor the plastic bits, by the salt water. The metals will be subjected to corrosion of salt water, unless rinsed thoroughly of the salts. The sandy grit would grind away at the surfaces of the carbon fiber legs and the plastic bits like leg locks.

