yep... what he said.
Get a flush kit (if you don't have one)
Basically, salt will make the ski ugly quick. When I lived in SoCal, I ran my stuff in the ocean all the time, and you would never know it, because I kept them clean.
The flush is simple. Just hook up the hose... start the engine... let it run for a little... turn off the water... then blip the throttle a couple times to clear the exhaust.
a) DON'T turn the water on first, or shut off the engine first. If the water is flowing, and the engine isn't running. You can fill the engine with water.
b) Don't run too long after turning off the water. You don't want to overheat the engine.
After that... give the ski a good bath, inside and out... then spray the engine, and pump parts down with some storage oil.
If you do that every time... it will look good for years to come.