Bring 3 cups of water and 1 teaspoon sea salt to a boil in a large heavy saucepan over medium-high heat. Gradually whisk in grits and return to a boil. Reduce heat to medium-low and cook, whisking often for 12-15 minutes until thickened. Whisk in milk and cook, stirring constantly for 5-7 minutes or until grits are creamy.