When pumping into the bottom, the real time energy use varies with the tank's rising and falling water level whereas the video only addressed equal height scenarios to address the…

The video below explains pressure in a water column.
https://www.youtube.com/watch?v=HlvHczb2vN4

It is explained several times in the video I linked and by my own explanation but let's look at it another way.
Victoria's Thomson Dam in Gippsland has a capacity of…