Many Readers Seem to Have Entered Into a Misunderstanding

Neither in the manga nor in the animation, there has never been a situation where the ability user cannot use the ability and is completely weak after being splashed or poured by sea water.

Symptoms of weakness only occur when the condition "at least a large part of the body is submerged in water" is met.

Otherwise, in a sea battle, if a wave hits the side of the ship, the splashed water can directly wipe out all the capable users on the deck.

Don't think that those who can overcome the ability of the sky can't touch it at all when they see "sea water". Only falling into the sea is a threat to capable users.