It says on the instructions dissolve one sachet in 62.5ml of water but also says for the chocolate flavoured sachets to dissolve 12 sachets in 750ml of water. I was wondering if anyone has did this with 12 sachets and how long does it keep for once mixed as she has only to take this twice daily? Will this mixture actually last 6 days? Help... her first dose is due about now. many Thanks, Dawn