I've just switched my 4.5 month old DS to 3 bottles in the day (at 10am, 1pm and 4pm) in preparation for going back to work. He's having Aptamil. And I'm breastfeeding him at 7am and at around 7:30pm when he goes to bed. Should I be giving him water in between or is he getting enough liquid? There doesn't seem to be that much time between feeds anyway as he is having milk every three hours during the day.