You can add a banana to the mixture and use melon that you have or like. You can add flax seeds, Chia seeds or protein powder. Milk is up to you. I love almond milk, and yes, you can even add "Soft (silken) tofu for extra protein. In the summertime adds some ice, it's perfect and refreshing. You can also cube melon and place in the Ziploc bag, then in the freezer. It's like melon ice cubes which are great for smoothies. Actually, any frozen fruit is perfect for smoothies.