Check the fluid you have attached to the cell zone, and the domain scale. You won't be the first person to have picked the wrong fluid or accidentally scale from m to mm / mm to m in a model.
You've picked up that the result is rubbish - that's a good start. Have a look in Learning and Help as I'm sure there's a mixing tank example/tutorial somewhere on the system.
You are navigating away from the AIS Discovery experience