Let me see if I understand this.
1. You measure a voltage between the tank and the ground on the power strip.
2. This voltage is present whether the grounding probe is plugged in or not.
3. The voltage goes away when you unplug the pump.
A couple of ideas.
1. It's not current leaking out of the pump, but the field generated by the coils of the pump that is causing a current and therefore a voltage drop between the tank and ground. It would have to be a big field, but it's possible.
2. If the pump is actually leaking, which would be really dangerous, then you should be able to measure a finite resistance between the tank and the pump's plug (unplugged of course). I am hoping that your voltmeter is a multimeter and can be used as an ohmmeter as well. Unplug the pump, put one lead of the ohmmeter in the tank, one on a prong from the pump (check all 3). It will give you a reading if there is contact between the pump and the water. It will not give you a reading (open circuit) if there is no contact.
3. What's going on with the ground lead? If it's functional, there should be only a small resistance between the two ends. So is it getting to ground? One thing that should work is plugging it into the same powerstrip as the pump, and checking the voltage again. A functional grounding probe will short out the voltage drop between the tank and the strip, and the meter should read 0 V.
4. The pump may actually be generating a stray voltage in the ground of the powerstrip. In effect, the voltage you're measuring is in the strip, not the tank. This is unlikely, assuming the contact between the powerstrip and house ground is good.
5. The third prong of your outlet is not really grounded. This does not exclude any of the other ideas, but would complicate your measurements of tank voltage, because you wouldn't be comparing the tank to ground, just a floating point.
As far as the whole chlorine thing, I am still baffled. If there is electrolysis generating chlorine and ultimately hypochlorite ion, then the volatge should be enough to ring your bells.
I hate to pass the buck, but I am not a chemist. This sounds like a question for Randy Holmes-Farley over at Reef Central. You might assemble all of the details you have presented here and ask him.
1. You measure a voltage between the tank and the ground on the power strip.
2. This voltage is present whether the grounding probe is plugged in or not.
3. The voltage goes away when you unplug the pump.
A couple of ideas.
1. It's not current leaking out of the pump, but the field generated by the coils of the pump that is causing a current and therefore a voltage drop between the tank and ground. It would have to be a big field, but it's possible.
2. If the pump is actually leaking, which would be really dangerous, then you should be able to measure a finite resistance between the tank and the pump's plug (unplugged of course). I am hoping that your voltmeter is a multimeter and can be used as an ohmmeter as well. Unplug the pump, put one lead of the ohmmeter in the tank, one on a prong from the pump (check all 3). It will give you a reading if there is contact between the pump and the water. It will not give you a reading (open circuit) if there is no contact.
3. What's going on with the ground lead? If it's functional, there should be only a small resistance between the two ends. So is it getting to ground? One thing that should work is plugging it into the same powerstrip as the pump, and checking the voltage again. A functional grounding probe will short out the voltage drop between the tank and the strip, and the meter should read 0 V.
4. The pump may actually be generating a stray voltage in the ground of the powerstrip. In effect, the voltage you're measuring is in the strip, not the tank. This is unlikely, assuming the contact between the powerstrip and house ground is good.
5. The third prong of your outlet is not really grounded. This does not exclude any of the other ideas, but would complicate your measurements of tank voltage, because you wouldn't be comparing the tank to ground, just a floating point.
As far as the whole chlorine thing, I am still baffled. If there is electrolysis generating chlorine and ultimately hypochlorite ion, then the volatge should be enough to ring your bells.
I hate to pass the buck, but I am not a chemist. This sounds like a question for Randy Holmes-Farley over at Reef Central. You might assemble all of the details you have presented here and ask him.
