I have been requested by a pool management company to perform pool inspections. Run of the mill stuff except when it comes to testing the bonding of steel reinforcment within the perimeter concrete. I have viewed Mike Holts video Part (3) of equipotential bonding testing, and he demonstrates the remote ground/zero reference method. I currently use a Megger DET earth ground tester, and conduct 2 point resistance tests from know bonding point to all equipment.
I have tried the remote ground/zero reference to known bonding point and measured perimeter points throughout the pool. However, I'm alway around 0.022 volts and show hundredths of volts difference between each point, even to known non-bonded locations.
With this in mind I wanted an absolute value for reference. I took at 24vac 100VA transformer and feed my positive 24vac to my known bonding point. I then take the common output from the transformer into the common input of my 114 Fluke multimeter. I place a probe on the end of a nonconductive rod and the corresponding lead into the voltage input of my multimeter. With this set-up I can measure and record the voltage gradiant of the water, railings, ladders, and perimeter concrete.
Any insight on this method or other suggestions would be greatly appreciated.

As a note: my transformer is controlled by a emergency start/stop button with audible and visual indicators while in test. This unit is monitored and initiated at each test point by a helper/apprentice while I probe the bonding test points with my meter lead on a non-conductive rod.