Using ground probes in aquariums

[Brew12]

Random probe question....... or a probe-probe if you will.

Nicely played!

sump is fine? I will just do that

Yup, just the sump is fine imo. It protects the entire system as long as the return pump is running.

 

[citymouse]

Better late than never I guess...I bought a ground probe, glad I read some of this long thread, I hadn't installed it yet because I wasn't sure what the extra thing hanging off it was and I'm unsure if the plug is GFI protected...I suppose I should know this in my own home. Also...I've had a saltwater tank for about 11 years and never knew about or even considered using a ground probe, but often worried about the "what if" scenario! So thank you for this post from years ago...lol I'm going to go plug that probe in now!

 

[Thaxxx]

My tank is in place and can not be moved to put in a gfi. Can I plug this (see picture) into a power strip, and the probe into this portable gfi to protect the tank?
Thanks.

 

[Brew12]

My tank is in place and can not be moved to put in a gfi. Can I plug this (see picture) into a power strip, and the probe into this portable gfi to protect the tank?
Thanks.

You would plug this into the wall and then plug the power strip into this. The ground probe would then be plugged in anywhere.

 

[Futuretotm]

@Brew12
Not sure if discussed earlier in this thread, could you comment on Biorock (low voltage DC is applied to accelerate growth), I wonder how this plays into our aquariums...

 

[Brew12]

@Brew12
Not sure if discussed earlier in this thread, could you comment on Biorock (low voltage DC is applied to accelerate growth), I wonder how this plays into our aquariums...

I've looked into this and find it fascinating. Unfortunately, I just don't know enough about it. My understanding is that the coral needs to be attached to the DC source, not just in the vicinity. Could someone build a little DC source and apply 3 to 6 volts to an iron cage and try to grow coral faster? Sure. But, they would have to do massive water changes and calcium carbonate additions because of the chemical reactions being encouraged and the iron corroding into the water.

 

[jasonrusso]

@Brew12
Not sure if discussed earlier in this thread, could you comment on Biorock (low voltage DC is applied to accelerate growth), I wonder how this plays into our aquariums...

I've looked into this and find it fascinating. Unfortunately, I just don't know enough about it. My understanding is that the coral needs to be attached to the DC source, not just in the vicinity. Could someone build a little DC source and apply 3 to 6 volts to an iron cage and try to grow coral faster? Sure. But, they would have to do massive water changes and calcium carbonate additions because of the chemical reactions being encouraged and the iron corroding into the water.

My guess is that this is a closed loop structure with a power and ground attached to the metal. If you have a pump leaking current, it's more of an open loop. The water gets charged (saltwater is a good conductor) until it finds the best ground.

 

[Brew12]

My guess is that this is a closed loop structure with a power and ground attached to the metal. If you have a pump leaking current, it's more of an open loop. The water gets charged (saltwater is a good conductor) until it finds the best ground.

Not to mention that even DC pumps actually release AC into the water. You can't have a DC pump without carbon brushes connecting the rotor to the stator.

 

[Brian_68]

Not to mention that even DC pumps actually release AC into the water. You can't have a DC pump without carbon brushes connecting the rotor to the stator.

Unless of course you have a brushless DC pump.

 

[Brew12]

Unless of course you have a brushless DC pump.

A brushless DC pump sends AC to the stator. It's a complete misnomer.

 

[Brian_68]

A brushless DC pump sends AC to the stator. It's a complete misnomer.

DC pumps for aquariums don't have carbon brushes, nor brushes all together. That would get pretty messy underwater. Just mentioning based on your statement that you cannot have a DC motor without brushes which is not true. Tunze is a prime example.

 

[Brew12]

DC pumps for aquariums don't have carbon brushes, nor brushes all together. That would get pretty messy underwater.

Absolutely, which is why they all send some form of AC to the motor. The only reason they are called DC is because most of them use a DC bus to convert AC to DC and then back to some form of AC.

There is no true DC motor that does not use carbon brushes.

 

[Brian_68]

Absolutely, which is why they all send some form of AC to the motor. The only reason they are called DC is because most of them use a DC bus to convert AC to DC and then back to some form of AC.

There is no true DC motor that does not use carbon brushes.

Yes brushless do convert the DC to an alternating square wave to run, not a true sinusoidal.

 

[Brew12]

Yes brushless do convert the DC to an alternating square wave to run, not a true sinusoidal.

Alternating Current = AC, and an alternating square wave is AC. True DC would be a constant voltage output and they don't exist in our hobby. Well, at least not on powerheads or return pumps.
Wave shaping to make the output more sinusoidal can be done to improve efficiency and reduce noise but trust me.... physics don't lie. There is no such thing as a true DC motor that doesn't use brushes.

 

[jasonrusso]

I'm going to say that form of brushed motor went out of style in aquarium use years ago. "magdrive" pumps don't have brushes and they have been around for 20 years!! Wether it's an ac or DC, they all emit emf which will induce a current in any conducive media.

 

[Brew12]

I'm going to say that form of brushed motor went out of style in aquarium use years ago. "magdrive" pumps don't have brushes and they have been around for 20 years!! Wether it's an ac or DC, they all emit emf which will induce a current in any conducive media.

That is one of the beautiful things about DC is that it doesn't produce meaningful amounts of EMF. They just aren't very common anymore. The big advantage of DC pumps used to be speed and torque control but VFD's (variable frequency drives) have negated that advantage. Now, DC motors are just a maintenance nightmare.

 

[Reefahholic]

@Brew12 Do you recommend a good place and brand to buy? Link?

I thought my GFCI would be good enough. I guess not.

 

[ccombs]

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.

@Brew12 when I first got into the hobby, I did not know about these and did not make arrangements to have one. Now that I am doing a rebuild, I am making sure I have one. I was never 'against' having one, but I am glad that people like you are here making the case for one and educating others. I also love that you even state what you are unable to counter.

 

[Brew12]

@Brew12 Do you recommend a good place and brand to buy? Link?

I thought my GFCI would be good enough. I guess not.

I don't. I just picked up a cheap one off of Amazon. They are such simple devices that I don't feel it matters. Just watch it for corrosion for awhile after you install it.

@Brew12 when I first got into the hobby, I did not know about these and did not make arrangements to have one. Now that I am doing a rebuild, I am making sure I have one. I was never 'against' having one, but I am glad that people like you are here making the case for one and educating others. I also love that you even state what you are unable to counter.

I feel this is something we need to have an honest conversation about. The hard part is making sure I give people the best information possible without becoming emotionally involved in their decisions. Electrical Safety is a big part of what I do for a living and something I am very passionate about so it can be a challenge. Fortunately, I can force people to do what I request at work!

 

[samnaz]

My setup isn't easily photographed because of how it is mounted in the tank but it is very easy to do.

For every pair of outlets you need an "Old Work" style 2 gang electrical box. It needs the plastic tabs that swing out to secure it, not the nail in type for "New Work".
https://www.lowes.com/pd/CARLON-25-cu-in-2-Gang-Plastic-Old-Work-Wall-Electrical-Box/1098507

Break out on of the bottom opening. Cut a hole in plywood (or other solid material) just large enough to slide the box into. Secure it in place by tightening the mounting screws.

For each outlet, I cut the cord off of a cheap power strip.
https://www.lowes.com/pd/Utilitech-6-Outlet-Power-Strip-Built-in-Circuit-Breaker/50211131

Strip back the end of the cord to expose the Black, White, and Green wires. Feed the prepared end of the cord in through the bottom of the electrical box.
Pick up as many 2 plug GFCI receptacles as you need.
https://www.lowes.com/pd/Hubbell-3-...-Indoor-GFCI-Decorator-Wall-Outlet/1000049969
Wire the cut end of the cord with Black on hot, White on Neutral, and Green on Ground.

Mount the receptacle into the electrical box using the screws on top and bottom.
Put on an outlet cover like this one
https://www.lowes.com/pd/Eaton-2-Gang-White-Double-Decorator-Wall-Plate/1101189

Plug the cord for each outlet pair into your apex.

The supplies to do this are cheap. Maybe I'll pick some stuff up and photograph the process to create a true DIY tutorial later in the week. Have company coming over today.

I realize this is years old now, just wondering if you ever did put together a more detailed how-to with photos of the process? You make it sound so easy (and cheap and obviously effective) but possibly above and beyond my electrical DIY skill level.