Everything causing stray voltage? What am I doing wrong?

[PPPPPP42]

I think I am going crazy or doing the test wrong somehow.
I just got a lawnmower blenny and noticed it was breathing fast compared to other fish. I checked online and the topic in a different forum referred to stray voltage as a possible cause. Whether or not its the cause is another issue, the stray voltage test I looked up is making no sense.

I put the meter (blue point so not cheap junk) on 200 AC and tested the outlet and it said 120v, I also tested the surge protector in the cabinet everything plugs into. Then I used an outlet checker to verify the outlet and the surge protector were working correctly.

Now to test for stray voltage I put the black wire in the 3rd prong ground in the outlet and put the red into the tank. I got 30v. When I unplug most things one at a time the voltage slowly drops until nothing is left plugged in (i think the skimmer was like 9v by itself which was the lowest) and then its just something like 2.5v or so which is the meter error I think because it shows that without even being in the water. There was one odd device (I forget which) where if I unplug it then the voltage shoots from 30v up to like 56v.

I would think I was in error here but testing an outlet with it everything reads as normal.

Just for the hell of it I repeated the test in a barrel of water in an outlet in the next room with a heater (rodi water) and got stray voltage.
That would be multiple pumps and heaters and the skimmer all making stray voltage.

I could make a list of what is causing what voltage but my fish are already getting bothered enough by stuff going on and off so not right now.

I just did another test to verify it isn't the meter, using the heater in the rodi barrel I took a household wire spool and put one end into the 3 prong ground on an outlet and threw the other end into the barrel and the 30ish volts the meter was showing instantly dropped to zero.

What in the heck is going on.

I will be going to menards to buy a 3 prong wire end and making my own ground only plugin to ground out all stray voltage from my tank unless someone tells me otherwise.

 

[WVNed]

Just make sure what ever you make the probe out of isn't attacked by saltwater

 

[W1ngz]

This may not be 'stray' voltage, just normal induced voltage because that's what happens when you have electric motors in saltwater. Every tank will have a certain electric potential, depending on equipment and placement.

The most reliable way to test for actual 'stray voltage' (which is actually a current leak) is with a ground probe and a GFCI outlet. If any equipment has a current leak and is truly exposing line voltage to the water, the GFCI will pop. A ground probe with no GFCI could electrocute a fish that passes through the path of the electricity, as it will provide a direct path to ground through the water.

 

[PPPPPP42]

It's doing the same thing in the barrel with just the heater plugged in.
Super weird thing, when I shook the heater and the thermostat turned it on the voltage reading actually dropped by at least 10 volts (I forget exactly) which was similar to when unplugging one of the cords from the main tank made the reading go from 30 to 56.

Something weird is happening and I still don't trust the meter is able to accurately record it but it seems possible to dump it to ground whatever it is.

 

[zalick]

Also try using an analog meter. Induced voltage is phantom voltage and an analog meter will read 0.

 

[W1ngz]

Ground probe and GFCI is your answer.

Magnetic fields interact, some positive and some negative. You can't just add them together and expect the sum of the individual components to add up to the measured induced voltage with everything running. That's not how magnetic fields work. A heater coil will behave differently than a motor.

Sure, a ground probe will 'dump to ground', but it's a solution looking for a problem, and could become a fire hazard without adequate protection on the outlet.

 

[762pmcs]

Firstly, are you sure it's reading volts, and not millivolts? This one gets me from time to time, and I use meters a lot for work.

Have you felt in the tank since noticing this? Did you feel a shock? Not suggesting you try this, just curious.

Have you tried to measure from wall outlet to tank?

Have you unplugged the power strip, then measured from outlet to tank?

I would unplug all items including any power strips or UPS, then measure after plugging in each piece of equipment. Process of elimination is probably the best method here.

 

[PPPPPP42]

Went through everything individually and tried both a jebao pump and some brand of heater separately (different than the ones in the tank) in a barrel with nothing else in it at the time.
Unless its a weird household wiring issue that neither the outlet tester or the meter can pick up at the different outlets there is nothing in common between the barrel test and the tank tests I did.

Its possible the issue is that I am using a digital meter since my last analog one broke quite a while ago. I will have to see if they still sell a decent one locally.
Still super weird that the meter shows the drop when I ground it so it is actually measuring something.

 

[Terry Mattson]

Gfi and ground probe, titanium. Do not make your own. Most metals will rust into your tank. Causing problems you do not want....

 

[CoralReefer1019]

Gfi and ground probe, titanium. Do not make your own. Most metals will rust into your tank. Causing problems you do not want....

I have the rid volt grounding probe, I have the probe in my tank and the other end plugged into a spare outlet. Where does the other part go with the thats attached to the plug?

 

[zalick]

Its possible the issue is that I am using a digital meter since my last analog one broke quite a while ago. I will have to see if they still sell a decent one locally.
Still super weird that the meter shows the drop when I ground it so it is actually measuring something.

Induced voltage has basically zero "energy" to it. A digital meter will detect the volts. An analog meter will dissapate what little energy there is and read zero.

Some higher end digital multi-meters have a low impedance setting so they can detect induced voltage. I don't have one. I use a cheap HD analog.

 

[PPPPPP42]

I have the rid volt grounding probe, I have the probe in my tank and the other end plugged into a spare outlet. Where does the other part go with the that's attached to the plug?

The little ring on the plug end is just in case its only a 2 prong outlet or doesn't have the ground properly hooked up, you can attach something to it else to ground it though you wouldn't need to use the outlet part at all then.

 

[Terry Mattson]

I have the rid volt grounding probe, I have the probe in my tank and the other end plugged into a spare outlet. Where does the other part go with the thats attached to the plug?

Do you mean gfi? The gfi would be in series with the wall outlet and the other end to your aquarium power strip. Having the ground probe plugged into the other outlet is great.

 

[ccombs]

Also try using an analog meter. Induced voltage is phantom voltage and an analog meter will read 0.

Huzzah! A man of electronics I see!

 

[theMeat]

Good advice to have gfci protection paired with a ground probe. The only way to go.
It won’t stop stray voltage but you’ll know in a fraction of a millisecond if you have any because the gfci will trip.

 

[CoralReefer1019]

Do you mean gfi? The gfi would be in series with the wall outlet and the other end to your aquarium power strip. Having the ground probe plugged into the other outlet is great.

Just have mine plugged into a power strip the part with the ground is just hanging off the plug

 

[theMeat]

If power strip is grounded it works, would prefer plug ground probe directly into any wall outlet that is grounded.

 

[ca1ore]

Unlikely stray voltage is the cause of your blenny's distress.

 

[PPPPPP42]

I assume it’s not an issue but I don’t like that there is something that I can measurably ground out in a tank full of creatures naturally sensitive to electrical fields.
It may have no real power to it but neither does what the fish can sense.
A gfci and ground probe are so cheap I’m not losing anything for the extra insurance.
I also plan to plug it into the surge protector which is grounded properly. I don’t want to basically wire around the surge protector directly to the tank.

 

[theMeat]

I assume it’s not an issue but I don’t like that there is something that I can measurably ground out in a tank full of creatures naturally sensitive to electrical fields.
It may have no real power to it but neither does what the fish can sense.
A gfci and ground probe are so cheap I’m not losing anything for the extra insurance.
I also plan to plug it into the surge protector which is grounded properly. I don’t want to basically wire around the surge protector directly to the tank.

Plugging the ground probe into a surge protector will work. Plugging the ground probe directly into wall outlet is better.