What is the fluid and what is the state in each tank? If it is in a liquid state, what is the level of tank that it is flowing into with respect to the tank it is flowing from? Is the liquid flowing into the top or bottom of the vessel? What is the fluid?
I was a high purity gas engineer with an integrated circuit fab and when I needed information that was not readily available, I contacted the gas supplier. They will not give you the software (usually) but can give you the design data.
Hope this helps.
Air Products
Matheson
BOC
All of these...