phew, I use about 2/3 of a tub per week, I do drink some water without it particularly when I'm very thirsty but it does help the water go down, I know drink about 3-4 litres a day (not including shakes). though it helps that my work has fizzy water taps in the kitchens so I can just fill up a refillable bottle about 3 times a day and have it on my desk.