I have a small above ground jacuzzi tub. It is made up of all plastic material. The only metal is the motor/heater unit. This jacuzzi is plugged into a standard 120 volt 60 hz g.f.i protected outlet.The electric outlet did not have a ground so I installed a ground clamp to the cold water system of my house and ran a #12 ground wire to the g.f.i. The jacuzzi is sitting on a brick patio slab.Recently I was standing on wet bricks barefooted outside the jacuzzi,and reached in the water to feel the temperature. I received a large shock and the g.f.i tripped off. There is a lug location on the motor/heater for a bond wire but I have nothing installed on it.How can I make sure this jacuzzi is 100% safe to use again?