Except is is described as ocean, and has the qualities of an ocean. It is relèvent as the spell is merely the dregs of what he is capable of and yet his influence is the ocean, are you seriously assuming that he got weaker then he finally got serious with rising to 50%? Because that seems like a fallacy on your part. As the tide was described as the ocean, so yes he is more than capable of lifting an entire ocean especially when said ocean is given the characteristics of an ocean unlike a sea is. He did show more power than when he lifted an ocean to above building level height when he brought it up to the sky. That is how much stronger he is. And the harbor is still connected to the ocean which is connected to other oceans which still has water in them, and when the remaining water after the vaporize returned to the harbor as well, it makes sense. KT, it is relèvent as she did not say a portion of the ocean by the ocean in general, unlike Gray who gave en estimate size, skullion is weaker than weakened Merc who was not 50% at the time without control of his powers