+1 as well, sea water is one of the most corosive substances on the planet. It will eat away the vinyl sheath around the light strand and then you will have exposed "hot" wire over your tank. Just does not sound like a great idea.
On top of that. They are too bright anyways. Fish need sleep just like every thing else! They say to not even keep your Lunar lights on all night, because of this. :zzz: