Help with halloween brain teaser. :)?

One gl is half full of magic potion and another gl is half full of water. A spoonful of potion is taken from the first gl and stirred into the gl of water. From that resulting mixture, a sorcerer uses the same spoon to take a spoonful and then adds it to the gl of potion. Is the quantity of potion in the gl of water now more or less than the quantity of water in the glass of potion?