It might be best to check the specifics on the MSR web site.
With that said, I would estimate it takes about 2-3 ml of water. The salt is used several times until it is all used up. A small packet of salt should last at least 5-10 runs. It runs for approximately 10-15 seconds. Regardless of the number of times you press the button, it makes the same amount of MIOX solution (2-3 ml), just more concentrated.

Pete