So...about stray voltage

[North Borders]

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

 

[sbash]

Wow, two bears in one night; it's time to put the internet down and get out my video games...

I'm not going to go too far into it, but the pumps (skimmer included) and inductive loads and visible voltage should be fine. The heaters though, are a resistive load (usually?) so that seems a bit odd to me.

Basically, electricity takes the path of least resistance. If you have a 'leak' in one end of your tank, and the ground probe in the other, then the 'leaked' power will go through the tank and could make things worse.

That said... All those things are in your sump; what about your power heads? If you put your arm in the DT and touch your light fixture (lol) do you get zapped?

 

[North Borders]

I tested the display too and the voltage is the same. I have a pair of MP40's for powerheads in the display. With everything in the sump off the display only reads like 1 volt with the mp40's running.

 

[North Borders]

Curiously, I heat my RODI storage container with a pair of Cobalt Neotherms and I tested that container and those 2 heaters are both putting out ~12 volts each.

 

[sbash]

Curiously, I heat my RODI storage container with a pair of Cobalt Neotherms and I tested that container and those 2 heaters are both putting out ~12 volts each.

Okay, so that's just how they fly then...

Based on the information you have provided, I doubt your issue is due to stray voltage... Maybe someone else will chime in

 

[bubbaque]

Wow, two bears in one night; it's time to put the internet down and get out my video games...

I'm not going to go too far into it, but the pumps (skimmer included) and inductive loads and visible voltage should be fine. The heaters though, are a resistive load (usually?) so that seems a bit odd to me.

Basically, electricity takes the path of least resistance. If you have a 'leak' in one end of your tank, and the ground probe in the other, then the 'leaked' power will go through the tank and could make things worse.

That said... All those things are in your sump; what about your power heads? If you put your arm in the DT and touch your light fixture (lol) do you get zapped?

I have had the light shock me before when my hand was in the water. What does that mean?

I do have a grounding probe on my tank now but am wondering if the shock meant there was something going on.

 

[North Borders]

I tested a Finnex titanium heater and an Eheim Jager that I had lying around. Both are same wattage as the Cobalts I use, but the Eheim puts out 4 volts and the Finnex only 2 volts. I was surprised by this as the Cobalts and the Finnex are both titanium.

 

[sbash]

I have had the light shock me before when my hand was in the water. What does that mean?

I do have a grounding probe on my tank now but am wondering if the shock meant there was something going on.

Is the ground probe in the sump or the display tank that got you zapped?

Let's say you have a power head in the opposite side of your DT as your return pipes. Your ground probe is dangling in your sump next to, say, your skimmer. The only path for that stray current to flow is from the powerhead through the DT, down the pipes and into the ground probe. Remember, electricity takes the path of least resistance, so with your arm in the tank and touching the grounded chassis on the light, you become that conduit. So, that COULD cause issues, and is likely the cause for the debate in the whole ground probe thing. However, by putting the ground probe next to the powerhead, or removing it entirely may be better for the livestock in the tank.

This thread is a good read:
https://www.reef2reef.com/threads/grounding-probe-or-no-grounding-probe.189489/page-2

 

[bubbaque]

Is the ground probe in the sump or the display tank that got you zapped?

Let's say you have a power head in the opposite side of your DT as your return pipes. Your ground probe is dangling in your sump next to, say, your skimmer. The only path for that stray current to flow is from the powerhead through the DT, down the pipes and into the ground probe. Remember, electricity takes the path of least resistance, so with your arm in the tank and touching the grounded chassis on the light, you become that conduit. So, that COULD cause issues, and is likely the cause for the debate in the whole ground probe thing. However, by putting the ground probe next to the powerhead, or removing it entirely may be better for the livestock in the tank.

This thread is a good read:
https://www.reef2reef.com/threads/grounding-probe-or-no-grounding-probe.189489/page-2

At that time I didn't have a grounding probe. I was just curious since it zapped me, did it mean I did in fact have stray voltage.

 

[sbash]

At that time I didn't have a grounding probe. I was just curious since it zapped me, did it mean I did in fact have stray voltage.

Ah okay... Yes if you get zapped, you have stray voltage... That said, given the induction devices and the electrical potential caused by the friction of the water moving (through the plastic pipes), it is probably unlikely to not have stray voltage...

 

[Daniel@R2R Verified Admin]

Doesn't a grounding probe need to be plugged into a GFCI outlet? I think plugging it directly into a power strip is a fire hazard.

 

[North Borders]

If I wind up doing a grounding probe it'll be on a GFCI.

So many conflicting opinions. Some folks say always have a grounding probe, others say never ever have one :/

 

[FredsNJReef]

Along these lines and not meant to hijack...what is the best spot to put the grounding probe? (I just ordered one earlier this week).

 

[North Borders]

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.

 

[FredsNJReef]

Ok so my return pump and skimmer and ATO are in the back section of my Fusion Nano and only the heater is in the DT. I guess the back area is where it should go.

Thank you!

 

[Greybeard]

Doesn't anyone own a meter these days? Test for VAC between the water and an electrical ground. You'll find out pretty quick if you've got an exposed circuit somewhere.

A grounding probe (or a titanium bodied heater... serves the same purpose) might one day save your life. After all, you could be sticking your arm into a live electrical circuit. The idea is to FIX the problem. If you've got enough electrical potential in your aquarium to zap yourself, SOMETHING in the tank is broken. You've got exposed metal in your tank, most likely, copper. Find it, and fix/replace it. Leaving an electrical connection open in your tank, expecting that a grounding probe is going to fix the problem, is _not_ the way to go here.

 

[North Borders]

Doesn't anyone own a meter these days? Test for VAC between the water and an electrical ground. You'll find out pretty quick if you've got an exposed circuit somewhere.

A grounding probe (or a titanium bodied heater... serves the same purpose) might one day save your life. After all, you could be sticking your arm into a live electrical circuit. The idea is to FIX the problem. If you've got enough electrical potential in your aquarium to zap yourself, SOMETHING in the tank is broken. You've got exposed metal in your tank, most likely, copper. Find it, and fix/replace it. Leaving an electrical connection open in your tank, expecting that a grounding probe is going to fix the problem, is _not_ the way to go here.

I personally don't get zapped when putting my hand in, but someone else replying in the thread said that they do. I bought my voltage meter last night, hence why I'm headed down the rabbit hole. My in water voltages are posted above. I grounded the black lead and red lead went in the water. "Zeroed" it on an outlet as well. The Cobalt heaters are titanium bodied, but when they come on they drop 12 volts into the water each. I own SEVEN Cobalt Neotherms (5 100's and 2 150's) and every one of them puts out about 12V when switched on. I don't think that they'll function as a ground, however, because they do not have the ground prong on their cable (just a simple 2 prong plug in).

All of this reading has been good at least as I realized that the wall outlet I'm running my Apex off of IS NOT a GFCI. I'm going to pick up a 3 way GCFI inline cable tonight and run the Apex off of that and if I wind up doing a grounding rod, it will be plugged in directly to the 3 way inline cable so it can trip the circuit and shut off the Apex if something goes bad. All of my in water sump equipment is plugged into the Apex.

 

[slapshot]

Oh boy I’ve wriiten a lot about this on another site but here is the readers digest version. I used to be a lineman when I was young so my thoughts are from real experience. Voltage is the potential for current. It is not inherently dangerous unless you give it a path to ground then you have current. Any number of things cause stray voltage including fluorescent lights above the water or just the difference in potential.

Let me start this by saying, no yelling, NEVER PUT YOUR HAND IN A TANK WITH ELECTRICAL DEVISES WITHOUT A GROUNDING DEVISE!!!!!!! Having said that keeping it in the water to “drain off” the voltage is of dubious benefit. When a bird sits on a wire nothing happens because he is at the same potential as the wire. Touch a ground and he’s dead. So by putting a ground plug in your creating current. Current is always bad for living creatures. Voltage isn’t typically and that’s the rub.

So then the question is which is worse for fish whose lateral line is sensitive or corals., voltage or current? I have run my tanks both ways. Can’t say it seem to matter. I only use a probe when I work on my tank. If left in I fear it will coverup a faulty piece of equipment. I do test my water with a meter whenever I do my water tests. Yes there is always stray voltage. So again I choose to go without, UNLESS I’M WORKING ON IT, I can not find any studies that suggest either one is bad but I know current is bad so...

 

[North Borders]

Oh boy I’ve wriiten a lot about this on another site but here is the readers digest version. I used to be a lineman when I was young so my thoughts are from real experience. Voltage is the potential for current. It is not inherently dangerous unless you give it a path to ground then you have current. Any number of things cause stray voltage including fluorescent lights above the water or just the difference in potential.

Let me start this by saying, no yelling, NEVER PUT YOUR HAND IN A TANK WITH ELECTRICAL DEVISES WITHOUT A GROUNDING DEVISE!!!!!!! Having said that keeping it in the water to “drain off” the voltage is of dubious benefit. When a bird sits on a wire nothing happens because he is at the same potential as the wire. Touch a ground and he’s dead. So by putting a ground plug in your creating current. Current is always bad for living creatures. Voltage isn’t typically and that’s the rub.

So then the question is which is worse for fish whose lateral line is sensitive or corals., voltage or current? I have run my tanks both ways. Can’t say it seem to matter. I only use a probe when I work on my tank. If left in I fear it will coverup a faulty piece of equipment. I do test my water with a meter whenever I do my water tests. Yes there is always stray voltage. So again I choose to go without, UNLESS I’M WORKING ON IT, I can not find any studies that suggest either one is bad but I know current is bad so...

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!

 

[Dragon52]

This has been interesting to read about. I've had no issues being in my tank but I always have my slippers on which have rubber soles so maybe that's why I've never felt anything.
I'll have to get my meter out & check.