So...about stray voltage

[Raptor72]

Let me toss this question since we’re here.

I’m wanting to add a stray voltage probe but can’t reach my outlet behind my tank (200gal). I have a 3 headed GFCI pigtail leading from the outlet to the open section of the cabinet where everything on the Apex is connected.

If I can’t screw the wire with the connector to the outlet box, there is really no reason to plug it in because essentially it’s not grounded right?

 

[North Borders]

I'm curious if any of the big livestock sellers use grounding probes of any sort?

 

[Brew12]

Let me see if I can set some things straight without getting too technical. We deal with 2 voltage sources in our tanks. One is induced and the other is fault.
And induced voltage occurs because alternating current is flowing through the tank (And yes, even DC pumps actually us AC current). The creates both an inductive and capacitive affect which allows voltage to be generated in the aquarium. This is very similar to how a transformer works. Unlike a transformer, there is a very high impedance between the electrical equipment and the water. If you add a ground probe to a the system it shunts current to ground. With the high impendence, it only takes a few milliamps of current to drop all of the voltage to zero.

Fault voltages are a different story. These occur when the insulation of an electrical device fails exposing an energized conductor to the water. This conductor is most likely copper. A copper conductor, carrying electricity and exposed to salt water, will corrode very quickly. This copper can adversely impact any corals and inverts in your tank. It can also cure Ich!
If you have a ground probe installed and using a GFCI it will trip the GFCI and de-energize the device. Not only are you more likely to notice the trip so you can investigate, but by de-energizing the fault it reduces the rate copper is released into the system
If you use a ground probe without a GFCI and the fault is bad enough, you will likely trip the breaker feeding the tank. There is a very low range of resistances where a ground probe can make this condition worse. Odds of it happening? Very slim, but technically possible. Since this condition is also more likely to speed up the failure mode it isn't likely to last long before tripping the breaker.

This is why I recommend running everything that gets wet on a GFCI with a ground probe. I do not recommend running everything on one GFCI for reliability reasons. It can be accomplished many ways. In your case, keep the MP40's off of a GFCI so if you lose your return pump it won't cause you to lose all flow. Your tank will be fine for hours this way.

Some other questions I have seen... If your titanium heater has a 3 prong plug you do not need a separate ground probe. You can plug in your ground probe anywhere. Even your neighbors house. It will still work. It doesn't matter where you install the ground probe. The water is conductive, as long as your return pump is running the entire tank is protected.
And finally, current won't flow through fish. They are less conductive than the water around them. This is why you can only electrofish in fresh water, not salt water.

Hope that helps!

 

[North Borders]

Is the inductive voltage worth ridding from your tank? Can that cause coral issues?

My titanium heaters do not have grounding plugs on them. Maybe that's why I saw the big difference with the Finnex titanium heater as that has a 3rd ground plug on its power cable.

 

[Brew12]

Is the inductive voltage worth ridding from your tank? Can that cause coral issues?

My titanium heaters do not have grounding plugs on them. Maybe that's why I saw the big difference with the Finnex titanium heater as that has a 3rd ground plug on its power cable.

It isn't known if an induced voltage can cause coral issues. No studies have been done on it. There is a little evidence that says induced voltages can cause HLLE in fish but even that hasn't been proven.

 

[North Borders]

Thanks for taking the time to check out my thread, Brew
I think I'll try adding the probe on tonight.

 

[Brew12]

Thanks for taking the time to check out my thread, Brew
I think I'll try adding the probe on tonight.

Any time! Thanks for the invite!

 

[slapshot]

How much stray voltage do you normally find in your tank? So you're saying you only run a grounding probe when you are working on the tank and take it out at other times?

Thank you for all the great replies so far everyone!

Yes, I put it in when my hand goes in and I take it out when I’m done. My tank runs about 6 volts

 

[Dual40IM]

From what I've read it seems to vary depending on which piece of equipment takes a dump. If its in your sump and a powerhead in the display goes hot, you'll create current from the display to the sump and everything in between.

For me, nearly all my equipment, minus 2 mp40's is in the sump, so it would be a no brainer to put it there.

The MP40's should never put any electric into the tank cause electric portion is outside of the tank and glass is an insulator.

 

[Brew12]

The MP40's should never put any electric into the tank cause electric portion is outside of the tank and glass is an insulator.

To clarify this... and MP40 cannot put dangerous amounts of electricity into a tank. They will induce voltage into the tank which can be read on a meter if no ground probe is installed.

 

[BuddyBonButt]

Hi all. I've been trying to trouble shoot my tank for a while now. Quite a few of my SPS have started to STN from the base and I've lost several LPS pieces including an acan colony and some cyphastarea and montis. My latest test tonight was to see if I have any stray voltage in the system.

When all my equipment is turned on I'm sitting at about 42 volts. Breakdown per equipment piece is as follows:
Skimmer (Octo 110ss): 4 volts
Return pump (Eheim Compact+3000): 6.5 volts
GFO + Carbon pumps (Cobalt MJ's): ~6 volts each
Heaters (Cobalt Neotherms x2): about 10-12 volts each

I've seen some posts that say any voltage at all is bad and I've seen other posts where they say don't worry til it's above 20 volts and even others where they say not to worry til it hits 40 volts. As an experiment I checked a couple spare heaters I had lying around and they both test at 4 volts each.

Is it worth grabbing a grounding probe? If I do do the probe, can you attach it to a power strip or does it need it's own dedicated line to an outlet? Will one probe pull out all ~40 volts?

So confused

I get buzzed when I just tried my ehime heaters. I wouldn't say Zapped. It feels like one of those trick pens you would get as a kid. It doesn't hurt it just tingles your fingers aggressively. So I guess my heaters are dead? If I can't put my hand in it, then I shouldn't be putting fish into it right?

 

[ocncheffy]

I get buzzed when I just tried my ehime heaters. I wouldn't say Zapped. It feels like one of those trick pens you would get as a kid. It doesn't hurt it just tingles your fingers aggressively. So I guess my heaters are dead? If I can't put my hand in it, then I shouldn't be putting fish into it right?

I had this with an old Hydor powerhead. Buzz like those “trick pens”. Tossed the powerhead in the trash after I narrowed it down.

 

[BuddyBonButt]

I had this with an old Hydor powerhead. Buzz like those “trick pens”. Tossed the powerhead in the trash after I narrowed it down.

Yeah no my ehimes are fine lol. It was weird I had my mixing pump going, put the ehime in and got buzzed. Took out the heaters and I was fine. Tossed in a cheap heater I got from petco. Few hours later, I put in a brand new Eheim heater got buzzed again. I was like no way that these heaters aren't submersible. And there's no way I got three dead ones in a row. so I took out the brand new heater and went to go put in the cheap Petco one and got buzzed again. I unplugged everything and looked closer. This is what I saw.

I have no idea why it didn't buzz me the first time I removed the old heaters but problem solved. Mom got me a new mixing pump for Christmas so all is well. It was about time too because in order to get the mixing pump started, I'd have to bash it with a rubber mallet.