I have never used a technique like this for anything other than the very first "Lab session" in Electrical Engineeing at college about 45 years ago!
The Lab was entitled "Equipotential Plotting" and involved measuring voltages in a perspex tray filled with water while a current was flowing from conductive bars at opposite ends of the tray.
The tray was about 10" long and the water was about 0.25" deep.
The purpose of this was to illustrate current flows in irregular shaped conductors and that not all the conductor material actually contributes to the flow of current.
So, back to the future and Mr Als question.
If it is possible to establish a current flow from an electrode in the pool to an electrode in the earth surrounding the pool, then measure the potential gradients in the pool, they should point to the area of the leak.
So Mr Borman, I did learn something in your classes after all!
JimB