Using ground probes in aquariums

Brew12

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Why is it that some people refuse to put a grounding probe in their aquarium? I've seen many arguments against using them, some of which are based on what I believe to be bad information. I want to make the case for why every aquarium should have a grounding probe installed.
We have these beautiful aquariums full of salt water into which we place electrically operated equipment. Everyone has heard the phrase "Water and electricity don't mix" and it is especially true of salt water. Yet this doesn't have to be dangerous and a ground probe is key to making this safe.

An electrical shock occurs when current flows through a person. There are three main factors that impact the severity of the shock. The amount of current flowing through the person, the length of time they are being shocked, and the path the current takes through the body. For a shock to occur a person must be touching an energized conductor and a source to ground. The glass and acrylic most aquariums are made from are excellent insulators. If a pump or heater develops a fault in the salt water, it will raise all of the water in the aquarium to the same voltage as is available at the fault, typically close to 115V. If you are touching the metal housing of a light fixture or standing on wet concrete and touch the water, you become the best path for the current to take to get to ground. These shocks are most likely to take the most dangerous path, which is through our heart. It will go into the hand, through the heart, and either out the opposite hand or down through our legs. This is one way the ground probe keeps us safe. Electricity always takes the lowest resistance path to ground. The human body does have some resistance so a properly maintained ground plug will always offer a lower resistance path to ground.

I would also make the argument that the use of a ground plug is important to the health of our marine fish, but not because of a risk of electrical shock. Scientists use electro-fishing techniques to collect or count fish populations by shocking fish. Electric eels hunt prey by shocking them with electricity. So why do I say marine fish are not at risk for being shocked? They live in salt water. Electric eels are a fresh water species and electro-fishing only works fresh water. In a fresh water environment the fish is more conductive than the water just like people are more conductive than air. You cannot shock a marine fish while it is in salt water since the water is more conductive than the fish. This doesn't mean that marine fish aren't affected by electricity.

It is a generalization to say that all of the salt water is at the same voltage in our aquariums. In reality, small differences in potential can exist within the water. Eddy currents of water will cause a difference in voltage. There will be a difference in potential caused by any air bubbles that may touch a fish. While these may not cause shocks, it can cause a serious irritation across the surface of the fish. I would also point out that you do not need to have an electrical fault to have a harmful voltage in your aquarium. Any energized cord either running in the water or along the outside of the tank will create a voltage in the tank using a process called induction. This is why many people see a voltage in their aquariums without having a GFCI breaker trip. A ground probe will prevent any voltage from building up in the aquarium water, protecting our fish from these small voltage differences.

Grounding probes also protect our tank from another problem that is much harder to see and correct. If you have an electrical fault in your tank, there is a high probability that you have exposed copper in your system. This copper will corrode in salt water and the corrosion is accelerated when impacted by electricity. Even if you use a GFCI, the circuit will not trip on a fault until you have a source to ground. A ground probe will immediately provide that path to ground. If you do not have a ground probe installed, you could be leaching copper into your system for days or longer until a path to ground from your water is established.

The one argument against using ground probes I cannot counter is that it could provide a heat source during an electrical fault. If you have an electrical fault in a very narrow resistance range, and do not use GFCI protection, it can act like a heater. I know I wouldn't risk the safety of my family and friends in an effort to avoid this one scenario. I hope after reading this you won't either.
 
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143MPCo

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Excellent write up, and I couldn't agree more!
 
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Brew12

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Excellent write up, and I couldn't agree more!
Thank you. I actually feel bad I didn't do this earlier. I've really struggled to come up with a way to explain the issues without getting either too long or too technical.
 
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Brew12

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Edited... pic didn't attach properly.
 
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Brew12

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I had a question asked of me that I thought would be worth posting here. Some grounding plugs, like the one I have pictured, have an extra ring terminal attached to them. This is provided to allow you more than one way to connect the ground. It will work just fine if you put the probe in your tank and plug it in. No need to use the extra terminal.

upload_2016-10-20_11-51-48.png
 

Bob Escher

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I lost five fish due to stray voltage from a bad heater a month ago. It was suggested voltage and I ran a multimeter test and could not detect anything, I didn't feel anything. I had intended to buy a ground and I decided after the multimeter reading why not better safe than sorry. I thought a GFCI outlet was fine. I got the grounding probe installed it and my EB8 on my Apex went ballistic with amps. Once I removed the bad heater Apex went back to Ok. It was a combination of the APEX and the probe that helped me. I'm not going to sit here and say a Apex will help go out and buy one. But I would have continued to not believe a heater was bad when it was working it was heating but there was just enough leakage to cause a problem

I'm a believer especially when the grounding probes are so CHEAP
 
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Brew12

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I've had one in every tank after I got knocked on my rear due to a faulty heater:eek::confused:
Sorry you had to go through that but I am glad you are using one now!

I'm a bit surprised that I haven't seen anyone trying to argue against using them like I have seen in past threads. I'm very glad that the opposition to these simple safety devices seems to be fading!
 
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Brew12

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Thanks Brew. Just ordered one. Been reefing for a looong time & never had one. $10 for piece of mind & safety is a no brainer!
Fantastic. Just knowing that one or two people are buying grounding plugs because of my post makes the time I put into this worth while!
 

ReeferMaddness843

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Well said! I agree they are a must. I installed a GFCI and Grounding probe shortly after I saw a thread about someone being shocked on here. I remember my biocube got me once really good as well and don't want that scare again. Prevention rather than hindsight.
 

Bob Escher

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I agree I hope my story helps even more. You can test with a multimeter and not feel a shock but it can still be there. Everyone one here tried to help figure why my fish were dying posted pictures, posted a video described everything and none of us thought about electricity. So yep for 14.00 dollars it's worth it I believe just as important as a GFIC outlet
 
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Brew12

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I agree I hope my story helps even more. You can test with a multimeter and not feel a shock but it can still be there. Everyone one here tried to help figure why my fish were dying posted pictures, posted a video described everything and none of us thought about electricity. So yep for 14.00 dollars it's worth it I believe just as important as a GFIC outlet
Not to mention a ground plug makes a GFCI much more effective. It is possible that a faulted electrical component won't trip a GFCI immediately because the insulating aquarium prevents current flow to ground. It won't trip until either you touch the water or you get enough salt creep. I don't want one GFCI tripping to take out my entire aquarium so I have decided to put each "wet" component on it's own GFCI receptacle. Hence what you see on my setup. This way one faulty heater doesn't take out my other heater, return pump, or skimmer. Each receptacle pair is fed from an Apex outlet so I still have full controllability as well as GFCI protection.
IMG_0526.JPG
 

AdamNC

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I use a ground probe and a gfci outlet. I have too much worth living for.
 

Bob Escher

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Not to mention a ground plug makes a GFCI much more effective. It is possible that a faulted electrical component won't trip a GFCI immediately because the insulating aquarium prevents current flow to ground. It won't trip until either you touch the water or you get enough salt creep. I don't want one GFCI tripping to take out my entire aquarium so I have decided to put each "wet" component on it's own GFCI receptacle. Hence what you see on my setup. This way one faulty heater doesn't take out my other heater, return pump, or skimmer. Each receptacle pair is fed from an Apex outlet so I still have full controllability as well as GFCI protection.
View attachment 411887
So you have your heaters on plugs separate from your Apex
 
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Brew12

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So you have your heaters on plugs separate from your Apex
Yup. Its an old picture, but the 4 cords in the Apex supply power to the 4 receptacle pairs. The top 2 are my heaters, the bottom left is my return pump, the bottom right is my skimmer. (Old picture, hadn't replaced my defective skimmer yet). It gives me full controllability and uses GFCI to isolate only the faulted component.

Edit: I guess I should have said no. My Apex still controls my heaters, only it does so through the GFCI receptacles.
 
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ReeferMaddness843

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Ah, I see now. Very similar look to what I use for drainage in concrete walkways. Lol! Either way, looks way cleaner and easier to use than zip tie everything together. I digress off topic a bit. Yes, safety!
 

Bob Escher

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Yup. Its an old picture, but the 4 cords in the Apex supply power to the 4 receptacle pairs. The top 2 are my heaters, the bottom left is my return pump, the bottom right is my skimmer. (Old picture, hadn't replaced my defective skimmer yet). It gives me full controllability and uses GFCI to isolate only the faulted component.

Edit: I guess I should have said no. My Apex still controls my heaters, only it does so through the GFCI receptacles.
So you have the gfci outlets plugged into the apex then? Do amps still show up
 

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