In ground concrete pool with fiberglass spa w/fountain attached. Common cool deck around everything. Up to 1.5 volts between the spa water and the pool water. I can feel a tingle when I put one hand in the spa, and the other in the pool. 12 volt light in both the spa and the pool. Heat pump type heater seems to trigger the event, but when it is turned off, I still get the voltage. It is intermittent, with no set pattern as to off and on. I am looking for ideas, suggestions, experiences, etc. as to what might be the problem. I did not do the original installation, so I cannot tell you if it was properly bonded. I get good continuity from the light fixtures trim ring to the handrails and the #8 at the pump and heater. It appears that there is a #8 from each wet niche back to the pump/heater area, both tied under a mechanical lug on the heater, with one continuous to the pump motor. Any input would be greatly appreciated. p.s. I am new to this forum, and apologize if this is posted in the wrong place. Thanks in advance. bc (Also, does the NEC require the bond to be continuous with no splice, and should the spa/fountain be GFI protected?