Grounding probes....are ya "fer 'em" or "agin 'em"

[ErikS]

Since this has come up twice lately I thought I'd start a discussion on the subject. I'll preface by saying I'm still undecided. I have one installed on my old tank but I have yet to do it on my new tank. I understand, to some extent why we use them......but....way back in my little pea brain the physics of electricty nag at me. From what I've read (& know of electricity) the "agin 'em" arguement goes like this (from another post) -

 

Electricity in a tank is isolated, it has no path to ground = it doesn't flow though the tank (& livestock). Much akin to the way birds sit on high tension lines or the way super high tension lines are repaired (the workers "clamp on" ). When a grounding probe is in the water the current flows through the water (& the livestock) to ground. It will travel from the source to the grounding probe. If the source is close to the ground then NBD, if it's at the opposite end of the water column then it will flow through all the livestock.

 

Another example, if you were in a bathtub FULL of water & a toaster fell in - if there were no path to ground you'd feel a tingle at best - you'd be dead if there's a metal drain...aka......a path to ground.

 

Without a path current doesn't flow.

 

That said I'd like to see a discussion on the pros & cons of grounding probes.

[mogurnda]

Without the grounding probe YOU are the path to ground. I have no opinion about fields and HLLE or any of that, but I am an electrophysiologist, and current passing through tissue has been my job for many years.

 

Here's a scenario: a powerhead has a leak and puts wiring in contact with water. If the tank isn't grounded, it goes nowhere until you put your hand in. Once you are in contact, you form a path to ground, albeit a high resistance path (probably a few megaohms). Depending on what you are in contact with, you could get a nasty shock.

 

With a grounding probe, there is a very low resistance path to ground. This means a couple of things. First, if you installed a GFCI, it will trip when your powerhead leaks, and you will have the opportunity to find the bad powerhead with a little troubleshooting. Second, it will shunt the current that would have gone through you. Same principle as grounding an appliance.

[ctreptow]

I have to agree without a path to ground it should not be a problem for the livestock, but it is. From my expereince I had problems with polyp extension. I have a yellow monti digitata that would not extend it's polyps during the day. When I put my ground probe in the polyps shot out within 5 minutes, and have been out ever since. So I have to assume that even in the closed system there was still a path to ground.

 

Chris

[Lee Stearns]

Ok - I admit I am only going by RC threads that have mentioned grounding probes in a positive light from circumstantial observations of their tanks, with no real scientific understanding- IE for removing a source of HLLE in Tangs and for almost instant improvements in corals polyps opening-

I would say for safety reasons alone it might be advisable. I remember in the long ago and far far away times that I would get mildly shocked every time I reached into one of my tanks.( yea I know that explains a lot) A grounding probe would have prevented this-(I think). I know if it is too great a fault it should pop the RFI breaker that ALL of our tanks are now running on Right! Hope every one is running their eqipment from a GFI plug- they are easy to install and it is important.

 

But back to electrical flow vs a charged system- I think the fact that there is a device (usually heater, but could be any other device including these sealed pumps) that is leaking electricity charges into the water and changes the ionic state of the many various chemicals in the water. By taking that usually small charge off the system you allow the the salt water and all its various compounds to remain in a more natural state. Electrical or chemical guys jump in here- this would be a great question to put before The RC chemical guru Randy.

My view for less that 10 bucks it can't hurt.

[ErikS]

Makes sense to me, I should have included it in the 1st post but that's really why I ran a probe in the old tank - no GFI. I agree, one of my goals (apparently unlike Howard) is to NOT be the best path to ground

 

But if all power is through a GFI is there really a reason to use a probe?

 

My view for less that 10 bucks it can't hurt.

 

ROTFLMAO - That's exactly what the other side of my pea brain says "couldn't hoit"

 

The issue with polyp extension may be due to the current in the tank. I know from talking to folks who work on high tension lines that being "clamped on" and having the current flow through you is uncomfortable - it may bother the corals.

[flowerseller]

I'm for a properly installed grounding probe.!

 

However, the GFCI is the most important piece of equipment your tank and family have.

A "properly installed" GFI will never let you feel the current.

 

The grounding probe has little or nothing to do with a benifit for you but plenty to do with the inhabitants.

Lateral line disease being one of the most visible effects.

However, the probe will not be benificial unless the box itself is grounded.

 

Those with titanium core chillers are not in need if a probe as the unit grounds the tank.

[Lee Stearns]

Eric,

We must have posted at the same time- I think not having charged particals outside of the natural salt water balance would be reason enough from anecdotal indications on polyps extension or HLLE. I think there can be small charges that do not create enough to trip the GFI.

Regards,

[ErikS]

Those with titanium core chillers are not in need if a probe as the unit grounds the tank..

And now ladies & gentlemen we have proof that it's a pea brain I completely forgot that a chiller is, among other things, a big grounding probe.....so let me re-phrase...

 

I'm running a grounding probe on both my old tank AND my new tank.

[mogurnda]

Has someone finally done a study on stray voltage and HLLE, or is it still anecdote? There have been so many causes given, and it would be nice to have some real data to look at.

[Lee Stearns]

From what I have read HLLE cause is still unknown- though they list about 5 things that have been known, when corrected to relieve or cure it- The two most promising are Vitamin A increase and installing an elctrical discharge probe.

Some anecdotal evidence as to lighting- but not neccessarily as an independent factor.

[flowerseller]

proof that it's a pea brain

ErikS, don't be too hard on yourself, I heard more like the size of a brussel sprout.

[HowardofNOVA]

"Has someone finally done a study on stray voltage"

 

I read a while ago about a study somewhere on the very subject!

 

One of the things I ready besides the safety issue is the build up of static electricity coming off of all the electrical lines, etc and that the negative effect it has on both corals and fish. They mentioned especially tangs are quite succeptable to this condition and STRONGLY recommended having a Ground Probe attached to any system. Of courese it took me almost a year to get one!

The article mentioned that with the release of buildups of these electrical charges that almost immediate changes of their coral polyp extensions where apparent!

Either way, for the SMALL charge...investment into your system, I'm now putting this down as cheap insurance along with a GFI!

Howard

[ErikS]

ErikS, don't be too hard on yourself, I heard more like the size of a brussel sprout

 

That must be why my wife calls me a cabbage head so frequently

 

[mogurnda]

"Has someone finally done a study on stray voltage"

 

I read a while ago about a study somewhere on the very subject!

 

One of the things I ready besides the safety issue is the build up of static electricity coming off of all the electrical lines, etc and that the negative effect it has on both corals and fish. They mentioned especially tangs are quite succeptable to this condition and STRONGLY recommended having a Ground Probe attached to any system. Of courese it took me almost a year to get one!

The article mentioned that with the release of buildups of these electrical charges that almost immediate changes of their coral polyp extensions where apparent!

Either way, for the SMALL charge...investment into your system, I'm now putting this down as cheap insurance along with a GFI!

Howard

30537[/snapback]

Can you give a link, Howard?

[fishface]

About a year and a half ago, a friend was over and we were running and re-routing electrical stuff in my kitchen prior to a full renov.

 

At the end of the day we were kind of goofy, and he was walking around with the inductive current tester. After testing the Wives, the cats, and some inanimate objects he held it to my 75 gal Freshwater Tank and the thing goes wild. We isolated the leak to one of two identical canister filters. I bought the ground probe the next day. (My Reef tank arrived a few months after that experience).

 

So the probe is really helpful preventative maintenance for the time when an item become slightly degraded but not leaking enough to trip something.

[GaryL]

i just bought 2 even though i have a gfi running. i will try it out for kicks and giggles.

[Grav]

Pro- grounding. Never heard anything thing to tell me they were less than required

[GaryL]

ok i just added to both of my tanks. i might be crazy but i think my montipora has opened up more. i hope so

[BeltwayBandit]

Coun't me in on the pro-grounding crowd. From what I understand a GFI is a great investment (I have my tank on one). But, the water in the tank is basically ungrounded. Therefore, if there is a short and you are "leaking" current there is no path to ground and the GFI won't trip. The grounding probe provides that path, and allows your GFI to work properly. Without a probe, the aquarist is usually the path to ground when you stick your hand in the tank. I had a light fixture that was shorting out with condensation. The GFI didn't trip, until I stuck my hand in the tank and got zapped.

 

BB

[steveoutlaw]

PRO PRO PRO!!! I don't know about all the electrical muckity muck, but I do know that when I got my 120g set up my yellow tang got HLLE. I put a grounding probe on and it started going away.

[ErikS]

Dang, what is it with you folks & your penchant for becoming the best path to ground?

 

A cicuit need not be grounded for a GFI to trip. A GFI constantly monitors both legs of a circuit (the hot & neutral), any mistmatch & it trips (which is why they can trip for MH - initial startups cause a mis-match). They should detect a 5mA difference, which depending on location is enough to give you a nice "buzz". If functioning properly it shouldn't ever allow enough current to kill (6mA across the heart IIRC) you.

[BeltwayBandit]

Dang, what is it with you folks & your penchant for becoming the best path to ground? 

 

A cicuit need not be grounded for a GFI to trip. A GFI constantly monitors both legs of a circuit (the hot & neutral), any mistmatch & it trips (which is why they can trip for MH - initial startups cause a mis-match). They should detect a 5mA difference, which depending on location is enough to give you a nice "buzz". If functioning properly it shouldn't ever allow enough current to kill (6mA across the heart IIRC) you.

30666[/snapback]

 

 

True, but if you do not have a path for that electricity to flow there will be no difference in potential between the hot and the neutral, until you stick your arm in the tank. That is where the grounding probe comes in. It gives a path to ground that is not the neutral leg, allowing the GFI to see the difference in potential between the hot and neutral leg.

 

An example would be a garden hose. Put a pressure guage on the main line and it reads the house pressure, open the valve to the hose and the pressure remains the same, but when you open the nozzle the pressure drops. The GFI is like the pressure gage, it can't tell the difference between the charged hose and the uncharged hose because there is no flow. Once the nozzle is opened (i.e. a path to ground) the pressure drops. This is what the GFI is measuring the difference in potential (pressure in my example) across the legs. With an ungrounded tank there is not necessarily an alternate path to ground to allow the GFI to see that difference in potential.

 

BB

[ErikS]

Well I could sorta see that if there were two bare leads in the water (though I'm not sure since I don't see the current making the trip back the neutral to complete the circuit)....but...in our case it's a device that's "leaking" current into the tank.

 

It's more like the same garden hose on a loop. The "GFI" would be like a pressure gauge measuring the pressure on both the outbound (hot) and inbound legs (neutral) - poke a hole in the hose (a voltage leak) - the outbound & inbound pressures no longer match = fault.

 

Though now we've moved away from grounding probes & into GFIs - which I believe everyone thinks is a good idea

[BeltwayBandit]

Well I could sorta see that if there were two bare leads in the water (though I'm not sure since I don't see the current making the trip back the neutral to complete the circuit)....but...in our case it's a device that's "leaking" current into the tank.

 

It's more like the same garden hose on a loop. The "GFI" would be like a pressure gauge measuring the pressure on both the outbound (hot) and inbound legs (neutral) - poke a hole in the hose (a voltage leak) - the outbound & inbound pressures no longer match = fault.

 

Though now we've moved away from grounding probes & into GFIs - which I believe everyone thinks is a good idea 

30698[/snapback]

 

But without a path to ground there is only a potential in the tank. There is nowhere for the current to go in an ungrounded system. The "leaking" current is like the nozzle on a charged hose, if you don't squeeze the handle the water doesn't move. So, going back to the tank situation where a device is shorted and "leaking" current, without a path to ground the system is at a higher potential but there is no current flowing, until the system goes to ground.

[BeltwayBandit]

Here is some info I found:

 

"Ground Fault Circuit Interrupters (GFCI or GFI) are special electronic devices to protect people from fatal electric shocks. Note, however, that you can still get a shock. There's an important difference between these devices and circuit breakers or fuses. Breakers and fuses are designed to disconnect power from a circuit when there is too much electrical current flowing. If too much current flows, the wires will overheat and create a fire hazard. Most circuit breakers are 15 or 20 amps, this equals 15,000 or 20,000 milli-amps. The bad news: it can take as little as 10 milli-amps to fatally shock someone. The good news: GFIs are designed to shut-off when it determines that only 5 milli-amps are "missing", presumably it could be shocking someone. "

 

So the GFI monitors flow in vs. flow out on the hot and neutral side of the outlet. If an item is shorted out in an ungrounded tank, the tank will be at a higher potential relative to ground, but no current will be "missing" to the GFI until that tank is grounded by either the aquarist or a probe. In an ungrounded tank the only path back to ground is through the neutral leg of the circuit. In that situation the GFI sees current in = current out. In a grounded tank the shorted device will go to ground somewhere other than the GFI, it will then see current in > current out and trip. (Many of the common culprits are two prong plug items so there is not an alternate path to ground if they short out, other than through you.)

 

So thats my $0.02 worth on this subject. My recommendation is a GFI and a grounding probe. Screw the fish (if it really is an issue to have current flowing through the tank when an item shorts), save the aquarist. As to my credentials I'm an Electrical Engineer with the US Coast Guard and I regulate power generation distribution and supply for commercial vessels.