Using ground probes in aquariums

Daniel@R2R · Oct 24, 2016

Good info on this thread! Thanks for sharing!

RobBaglieri · Oct 24, 2016

Waterjockey said:
The consumer devices we buy have UL or CSA certification or the like, do these grounding probes come with a UL or similar "stamp"?

Re the gravity/apple falling example, unfortunately, we don't seem to be able to agree on even what I thought were basic concepts...from my viewpoint, yes, it is much like arguing if the apple would fall from the tree or not.
Take your continuted repeated statement, that seawater is a "very good conductor" of electricity, that to me is like a person repeatedly insisting a solution of 6.9 pH is a "strong" acid. A "very good conductor", is say, copper. 1.68 x 10 -8 p(ohm*meter) at 20 deg C A good insulator, like hard rubber is 1.0 x 10 +13. Seawater is about 2.0 x 10-1. That is pretty close to the neutral point between the two. Notice copper is 8 significant digits to the right, and rubber is 13 significant digits to the left...and seawater is only 1 significant digit to the right? In my book, that is very close to being in the middle between the two, and what I consider a "good conductor" (copper for example) is about 10 million times more conductive than seawater. Will an electrolytic solution like seawater conduct electricity with enough force (potential) applied? Yes, certainly. Is it a "good conductor"? Certainly not.

We seem to stumble into disagreement in virtually every paragraph, and what I fear, is what happens so often when communicating via forums, newsgroups, email, etc, is the tone of text can come across to the reader completely differently than the intent of the author, and it quickly devolves into something unproductive. I'm afraid we are so far apart on just the basics, there is no fruit to bear in continuing on. So on that note, thank you for the discussion, may your corals grow fast and colourful and multiply, and may your fish be fat and healthy, cheers!

There is nothing wrong with disagreement. Disagreement breeds healthy debates. I find this thread very interesting and informative. Id like to see a consensus on the approach to the safest saltwater set up. I once got shocked from mili amps and high voltage performing electrophoresis. It was not fun. I learned to respect the combination of mili amps, voltage and condensation I will never forget V=IR

As for a pH and strong acids to, there is no correlation between pH and whether and acid is a weak acid or strong acid...just trying to start a disagreement here 8>P

Scarybo · Oct 24, 2016

Maybe its me... I'm missing the controversy on ground probes. They are very inexpensive and small and unobtrusive. Why wouldnt anyone install one on their tanks. It cant hurt. It can only help. We put our hands into a box of salt water that is packed with electrical equipment. Just my .$02

Brew12 · Oct 24, 2016

Scarybo said:
Maybe its me... I'm missing the controversy on ground probes. They are very inexpensive and small and unobtrusive. Why wouldnt anyone install one on their tanks. It cant hurt. It can only help. We put our hands into a box of salt water that is packed with electrical equipment. Just my .$02

As a huge proponent of them, I do acknowledge they have drawbacks.

The first is that if you use them with a GFCI (and don't have a more complex system like mine) a small electrical fault can take out power to your entire tank. If this happens while you are away it could cause serious problems. There are many workarounds, but this is one major drawback. Without the ground plug (and as long as you don't have salt tracking) the GFCI shouldn't trip until you put your hand into the tank. This way you will be home to immediately respond.
The second drawback is if you use one without a GFCI it is possible to pull enough current to heat the water without drawing enough current to trip the supply breaker.

Each of these situations can be accounted for but it is important to understand them so we can plan for them accordingly.

Scarybo · Oct 24, 2016

Brew12 said:
As a huge proponent of them, I do acknowledge they have drawbacks.

The first is that if you use them with a GFCI (and don't have a more complex system like mine) a small electrical fault can take out power to your entire tank. If this happens while you are away it could cause serious problems. There are many workarounds, but this is one major drawback. Without the ground plug (and as long as you don't have salt tracking) the GFCI shouldn't trip until you put your hand into the tank. This way you will be home to immediately respond.
The second drawback is if you use one without a GFCI it is possible to pull enough current to heat the water without drawing enough current to trip the supply breaker.

Each of these situations can be accounted for but it is important to understand them so we can plan for them accordingly.

I agree that there are drawbacks but if I have to choose between my tank crashing while I am away or me getting electrocuted, the choice is easy. I had a metal canopy in the past. A wire came loose and touched the metal. When I lifted that canopy with one hand and reached into the tank with the other it knocked me on my ..... I can always make adjustments to protect the tank in the event a GFCI trips. I should also make adjustments to protect my life.

Brew12 · Oct 24, 2016

Scarybo said:
I agree that there are drawbacks but if I have to choose between my tank crashing while I am away or me getting electrocuted, the choice is easy. I had a metal canopy in the past. A wire came loose and touched the metal. When I lifted that canopy with one hand and reached into the tank with the other it knocked me on my ..... I can always make adjustments to protect the tank in the event a GFCI trips. I should also make adjustments to protect my life.

Just so you are aware, in this case a ground probe could have made it even worse. A ground probe will only impact faults that occur inside the tank. An external fault, such as in a light or canopy, won't be impacted by installing a ground plug.
It sounds like there must have been something else going on in this case, and it can be very difficult to track after the fact. This forum is full of people who have been shocked when they touched their light fixture thinking it was the cause, only to find that they had a fault in the tank and that the metal lighting fixture only provided the ground path.

On the important note, I agree and would not have a salt water aquarium without both a ground probe and a GFCI. My son loves to put his hand in the tank so his friends can watch the cleaner shrimp in action. I would risk losing all my fish before I put his life at risk.

skim · Oct 24, 2016

Scarybo said:
Maybe its me... I'm missing the controversy on ground probes. They are very inexpensive and small and unobtrusive. Why wouldnt anyone install one on their tanks. It cant hurt. It can only help. We put our hands into a box of salt water that is packed with electrical equipment. Just my .$02

Well theory behind not having one is the Tank left on its own is not a completed circuit, meaning what ever Voltage is in the tank stays there not affecting anything inside, but as soon as you ground it via yourself standing on concrete floor or via ground probe you have completed the circuit and everything is going to feel it. Yourself, Corals Fish, Bacteria, Inverts. It is very rare for a Ground probe to remove all of the Voltage from aquarium and even small amounts one can feel if you have a Hang nail or cut and I am sure Corals and Fish being as sensitive will definitely feel it, so how long do like to stand there and feel that tingle, could you would you like to feel it 24/7 ? Now this is based on some one that feels they want to try and rid the Voltage and many including myself say do not bother because as the Circuit is not completed it is just floating voltage looking for an out. Now if you want to add a Ground probe because you are worried that Bill Bob Jr. or Marry Lou may happen to put their hand in the Tank or Sump on the same day that your Heater decided to let some water into it then that is different and that is when you want to use CFGI and a Ground probe and hopefully it trips when that Heater decides to go south, but just remember that now you have completed the circuit and everything in the tank is going to feel that Voltage, you have given it a way out. I believe the best thing to do would be find out what is causing the Voltage and fix it and then if you still want to add the CFGI.

Brew12 · Oct 24, 2016

skim said:
Well theory behind not having one is the Tank left on its own is not a completed circuit, meaning what ever Voltage is in the tank stays there not affecting anything inside, but as soon as you ground it via yourself standing on concrete floor or via ground probe you have completed the circuit and everything is going to feel it. Yourself, Corals Fish, Bacteria, Inverts. It is very rare for a Ground probe to remove all of the Voltage from aquarium and even small amounts one can feel if you have a Hang nail or cut and I am sure Corals and Fish being as sensitive will definitely feel it, so how long do like to stand there and feel that tingle, could you would you like to feel it 24/7 ? Now this is based on some one that feels they want to try and rid the Voltage and many including myself say do not bother because as the Circuit is not completed it is just floating voltage looking for an out. Now if you want to add a Ground probe because you are worried that Bill Bob Jr. or Marry Lou may happen to put their hand in the Tank or Sump on the same day that your Heater decided to let some water into it then that is different and that is when you want to use CFGI and a Ground probe and hopefully it trips when that Heater decides to go south, but just remember that now you have completed the circuit and everything in the tank is going to feel that Voltage, you have given it a way out. I believe the best thing to do would be find out what is causing the Voltage and fix it and then if you still want to add the CFGI.

What you are saying is true. Well, it is true for fresh water aquariums.

People get shocked because we are more substantially more conductive than the air around us. This makes us the preferred path to ground through which current will flow. In fresh water, fish are also more conductive than the water that surrounds them, so current will flow through them. This is how electro-fishing works. In a marine tank, the fish is less conductive than the water they are swimming in. This is why electro-fishing doesn't work in salt water. Any current flowing through the water will flow around the fish, not through it.
Voltage is a different issue. Since salt water isn't uniform there are differences in voltage along the surface of fish and coral. This would result in eddy currents flowing on the outside of the fish. While unproven, this is why some people suspect voltage leaks can cause Lateral Line disease.

If you have a salt water aquarium with a properly installed ground probe, you will have less than 1 volt to ground throughout your tank. If your voltage gets any higher than this you either need to verify you have it installed correctly or you should double check your meter.

Paul B · Oct 24, 2016

I love my ground probe. I am not like you guys who buy one. I don't buy anything. I use a stainless steel radio antenna. (or a spoon, knife, fork, backscratcher, knitting needle, bicycle spoke or anything I find that is not copper

)
Anyway, yeah I use it so I don't get shocked, but I don't want to get into that. If you like ground probes, use one, if not, go out to dinner and have a nice glass of Merlot. But besides that. I use my ground probe antenna sometimes to target feed my clingfish or spear a bristleworm.

Brew12 · Oct 24, 2016

Paul B said:
I use a stainless steel radio antenna.

I don't think my local historical museum is passing those out!

But I agree, a ground probe is absolutely nothing special. Just a non-corrosive conductive material that you can connect to ground using a wire.

As a bonus if you run a FOWLR, you can run a bare copper conductor into your tank and not only will not have to worry about getting shocked, but your tank will stay ich free!

renato120 · Oct 24, 2016

@Gui Paim

273629116 · Oct 24, 2016

Brew12 said:
You cannot shock a marine fish while it is in salt water since the water is more conductive than the fish.

But...How'd they kill Jaws at the end of Jaws 2? LOL
Just ordered my ground probe

Brew12 · Oct 24, 2016

Chris Macaluso said:
But...How'd they kill Jaws at the end of Jaws 2? LOL
Just ordered my ground probe

Obviously, they didn't, which is why they unfortunately chose to make Jaws 3!

And Welcome to Reef2Reef!

Rob's Reef · Oct 24, 2016

I just watched this video on ground probes... looks like they reduce some of the voltage but not very much... good little video if you have time.

Brew12 · Oct 24, 2016

Rob's Reef said:
I just watched this video on ground probes... looks like they reduce some of the voltage but not very much... good little video if you have time.

This video was posted earlier. If you watch the video, all he claims is that the bucket is full of water. I tried to repeat his experiment at work this past weekend with salt water and couldn't duplicate the results. When I used tap water, I was able to get close to his results. Had he used salt water, his breaker would have tripped immediately even without the ground probe installed.

Brew12 · Oct 24, 2016

Rob's Reef said:
I just watched this video on ground probes... looks like they reduce some of the voltage but not very much... good little video if you have time.

I'm really glad you posted this video because I think it will help to put some numbers to this. Understand that this is very oversimplified, but I think it will help when you look at the orders of magnitude involved.

If you have a 120V supply, and show 40V still in the bucket, that means 80V is being dropped across the water. If you pulled the full 20 amps available in the water, the effective resistance of the water would have to be 4 ohms over distance between the hot and neutral leads. In this video, we don't know how much current was flowing, so all we can do is assume the effective resistance is over 4 ohms.
Sea water has an effective resistance of 0.2 ohms over 1 meter. His lead were much less than a 1/2 meter apart. That should give us an expected resistance of 0.1 ohms. If we put a 120V source in the salt water as he did, it should draw almost 240 amps to ground which would immediately trip his breaker.

This video shows why a ground probe has no value in a fresh water aquarium. The video provides bad information if applied to salt water aquariums which is what the person who filmed it implies.
It is bad information like this that made me want to create this thread in the first place.

Rob's Reef · Oct 25, 2016

So is the grounding probe supposed to work better in saltwater or is is it less effective?

What I got from the video is even with a grounding probe you're still going to get shocked!