Sorry - I'm going to respectfully disagree. Condensation nuclei can be anything - not even necessarily the salt in the air. Read up some more.

Beyond that, you do realize how impossible it would be to completely "clean" ocean water, right? The marine life in the ocean depends on the salinity to survive. Ocean currents move in such a manner that removal of the salt from any large (let's grant you 100 square miles to whatever depth) amount would merely become impure in a matter of minutes if not less.

Besides, everyone knows that without condensation, the heat of the water builds up. The hurricane gets a lot of its strength from warmer water - and not because it helps cause evaporation