What is the relationship between the phases of the moon and extreme tides?

It's the pull of the moon that determines the tide pull. When it's low tide, and the waves are pulling back from the shore, it means that the Moon is starting to pull away from the Earth. The Moon's cycle pulls away, and comes back over and over in one day. That's what low and high tide are. When the waves are crashing to the shore, it means that the pull of gravity from the Moon is making the waves crash onto the shore. It all depends on the pull of the Moon, and the effect it has on the waves gravity.