I put 2 cans of formula and 2 cans of water for a total of 1000 ml in a Kangaroo bag. It despenes in about 30 to 40 minutes. It all depends on what you can toleerate. My thinking was that I could drink a liter of German beer in 30 minutes so I should be able to handle the formula. I sometimes can't and my GERD acts up. BTW I use 2 cans of TwoCal HN for morning and noon, and 1 can of TwoCal plus 1 can of Jevity 1Cal with fiber for evening. The former is rather dense and slow and the latter can run a lot faster. You can adjust the speed with your tube clamp or the roll clamp on the bagg set up. A pump drives me crazy it is so slow.