I put in a 18x40 liner pool with polymer walls last year. The kids have been complaining of a shock when they touch the metal coping while in the water. The light and coping where grounded during construction, we even looped the ground wire around the pool step and cozy cover for continuity. We used fiber in the concrete so there was no rebar to ground. While trouble shooting the problem I have grounded the pool pump with its own ground rod and did the same for the ladder with no relief. I have measured the voltage and it is between 1 and 2 volts when measured across the water and the coping. This is driving me crazy, does anyone have any ideas of what this could be?