What is the shelf life of the powder vs the liquid? Is it different after the container is opened for some reason? Why do you have to make a fresh batch of the medicine every day? I assume it breaks down in water? The store had the powder and liquid version of Amprolium so I looked at the expiration dates. The powder expires in Feb2019 and the liquid expires in 2023. Bought the liquid. Maybe they had an old batch of the powder, not sure. I don't expect to use all the medicine in the course so I want it to keep, just in case.