What you will notice

In the first minute: the powder cake lifts off the bottom of the vial and the liquid goes clear with a slow swirl. In the first week: nothing at all from the water, which is the point, and your doses read the same every time because the strength is even. Weeks two to four: a vial mixed with this water and kept past its day is the one to let go of, since nothing in it holds germs back. Longer: the habit sets in, and you keep sterile water for same-day mixing and bacteriostatic water for a vial you will return to.