Stray voltage, can I rule this out

[HouseofStark]

Have noticed as of late a few heads of hammer have had died off, and some with gapping mouths. I wanted to check for stray voltage. I plugged an extension cord into a nearby outlet because the one near tank is full. I placed the ground test lead in the ground of the cord and placed the positive lead in the tank water. I set the multimeter to lowest range and it seemed to hit zero when I placed it in the water. I then changed it to mV and I got a reading of 4-5. I turned on all equipment possible so I had everything running and seemed to again be 4-5 mV. Can a assume that stray voltage is not an issue.

Question, I have a digital multimeter that when I switch it to mV it would fluctuate from 10-25 mV out of water, but once placed in water and grounded, it pegged to 5. I assume its just reading the mV in the atmosphere when out of water?

 

[cdklos]

Have noticed as of late a few heads of hammer have had died off, and some with gapping mouths. I wanted to check for stray voltage. I plugged an extension cord into a nearby outlet because the one near tank is full. I placed the ground test lead in the ground of the cord and placed the positive lead in the tank water. I set the multimeter to lowest range and it seemed to hit zero when I placed it in the water. I then changed it to mV and I got a reading of 4-5. I turned on all equipment possible so I had everything running and seemed to again be 4-5 mV. Can a assume that stray voltage is not an issue.

Question, I have a digital multimeter that when I switch it to mV it would fluctuate from 10-25 mV out of water, but once placed in water and grounded, it pegged to 5. I assume its just reading the mV in the atmosphere when out of water?

Not sure man, but you can throw a couple of tank grounding plugs in the sump and don’t worry about it. You can get them on Amazon. $15 is a cheap fix.

Rio RV2735 Rid-Volt Titanium Grounding Probe https://a.co/d/aL7incs

 

[HouseofStark]

I had one of them, just connected it and dropped it in. Made sure it was connected to an actual outlet not any adaption. That electrical circuit has an afci breaker on it. Need or wish I could get to the outlet to change it out to a GFCI outlet also. But currently impossible

 

[kgstei]

I had one of them, just connected it and dropped it in. Made sure it was connected to an actual outlet not any adaption. That electrical circuit has an afci breaker on it. Need or wish I could get to the outlet to change it out to a GFCI outlet also. But currently impossible

They do have plug-in GFCI outlets like this.
Amazon product

 

[exnisstech]

I've had 50 volts in my tank. Yes 50 volts not mV. The only problem I had was getting the $&#* shocked out of me when I placed my hand in the tank. It was caused caused by leaking koralia powerheads. Fish, coral and inverts were all fine. Stray voltage is a red herring and to my knowledge no one has ever provided any proof of it causing problems with livestock. I think people use it when they can't figure out anything else causing mysterious issues in our tanks.
Even Jay Hemdal stated as much in post number 8 in this thread. https://www.reef2reef.com/threads/h...nyone-getting-desperate.991331/#post-11472130

 

[jda]

in all of my time, I have only noticed issues with corals if you can feel the voltage with your hands. Even in hangnails or other sensitive parts of the fingers. Otherwise, it has never been a problem for me.

 

[exnisstech]

in all of my time, I have only noticed issues with corals if you can feel the voltage with your hands. Even in hangnails or other sensitive parts of the fingers. Otherwise, it has never been a problem for me.

Not to be argumentative just trying to add more knowledge. What issues did you observe with corals when you had stray voltage?

 

[FUNGI]

But currently impossible

LOL....sorry, old electrician joke

 

[radfly]

Corals are not grounded… electricity is as harmless to them as it is to birds on a power line.