Do I have stray Voltage?

[PoonTang]

Well I am having troubles with the PE on my my acros and Milli's still. i was sure it was due to Red Bugs so I treated. I am seeing no improvement so on to the next possibility. Stray Voltage. I dont exactly know how to test for it so i put the neg probe on the ground terminal of my powerbar and the pos probe in the tank. I got a very erratic reading of 50 to 100 mVDC. Is this the correct way to test? and was that a bad reading to have?

[outacontrol]

is everything plugged into GFCI outlets?

[PoonTang]

is everything plugged into GFCI outlets?

Yes everything is on a GFI. I have 2 dedicated GFI circuits for my tank.
I just did a little bit more reasearch and found out that that you measure AC Voltage. I got 21. I started unplugging things and sometimes the voltage actually goes up.??? Most of the voltage is coming from my 2 Korrilia K4's but i can actually make the voltage go down by unplugging 1 that is not even turned on by my controller. Anyone else running Korillias that they can test? Is 21V even something to worry about, apparently stray voltage is linked ti HLLE and mysterious deaths neither of which i have.

[outacontrol]

I just went and tested mine, I have 27 volts ac from my tank water to ground.
Some from my ebo jager heater, some from the K1 and some from the K2.

Now I am interested to research this more, as an electrician 27 volts does not worry me on a safety point, but I do not think it is good. On a side note my freshwater tank has Zero volts from it to ground.

[mike31154]

Can't say for certain, but I don't think your coral problems stem from stray voltage. 20 to 30 VAC is not overly high. Besides, unless you have a ground probe installed, the voltage potential that you are measuring has no place to go until something (like your meter or a body part) completes the circuit between the water and ground. Otherwise it is just sitting there as a potential. If the circuit is completed by you or a grounding probe, then current will flow, the amount being dependent on the existing potential and the resistance of the path it takes to get to ground.

Aside from equipment submersed in your system, your lighting can actually impart a substantial charge to your water by electromagnetic induction. Especially fluorescents. Until I grounded each reflector on my T5HO retro set up, I would get a nice little buzz whenever my arm brushed against a reflector with my hand in the water. Other than this buzz, there should be no harm to the system inhabitants since there will simply be a potential difference between the light reflector and the water, so no electrical current flows until the circuit is completed, again, in this instance by my arm. Even then, once the current is discharged to the water through my arm, it has no place to go... unless there's a grounding probe to allow the circuit from the water to ground to be completed. Before grounding the reflectors I was measuring well over 30 VAC between them and the water, don't recall the exact number. As you can see, things can get pretty complex and confusing in a hurry.

Here are two links to articles by a Robert Michelson, Principal Research Engineer, Emeritus - Georgia Tech Research Institute. I think it's fair to assume that this is a trustworthy source for this type of info.

http://angel-strike.com/aquarium/GFI&TechnicalDetails.html

http://angel-strike.com/aquarium/GroundingProbes.html

I try to keep the electrical gizmos physically in the water to a minimum and run my system on two separate GFCI protected circuits. Only things I have in the water are two heaters and a small powerhead delivering water to my skimmer. VorTech pumps provide flow (electrics are on the outside of the glass) and I have no sump, so no return pump at this time. The more low voltage DC components you can use, the better. That way, electromagnetic voltage induction is virtually nil and safety of you and your livestock is greatly enhanced. The future is looking good in that regard with more LED lighting systems on the horizon as well as an increased selection of DC voltage powerheads and pumps.

[Ron99]

I have to disagree. I had a similar problem where my SPS lost PE and then started to bleach and die. I tried checking voltage with a volt meter and read about 1 volt. Tried checking everything else that was suggested or I could think of and nothing made a difference.

Then one day I put my hand in the tank with a recent cut on my finger and the cut was buzzing. It was definitely electrical in nature. So I started unplugging components and when I unplugged my heater, the buzzing went away. Plugged it back in and the buzzing came back. I bought a new heater and ground probe the next day and within 12 hours my SPS started to show PE again and are now recovering nicely.

So I suspect voltage leaks are more common, and a more common source of problems, then we all realize. Whenever you have electrical components submerged in salt water, even only one or two, there is a risk of one developng a leak and introducing voltage/current to the tank.

[PoonTang]

I never have any buzzing when i put my hand in the tank and have never had the GFI trip. I realize that I may be looking down the wrong avenue here in regards to my corals but I am running out of options and want to explore every possibility.
The more i read the more i think that my readings are not high and it is not a leak, just an imparted voltage from the electrical devices. My tank is not showing any of the classic symptoms of a voltage leak.

[mike31154]

Looking into any possibility or angle is always a good idea. As I mentioned, I try to keep the number of devices with electrical cords physically in the water to the absolute minimum. I don't have any SPS corals, so I do this for my own safety, not the livestock. I've seen a number of threads & posts regarding Koralia pumps going bad with regard to excessive voltage being introduced into the water. Heaters may also cause problems, particularly for those people who like to submerse the entire thing, control head, cord and all. I cringe every time I see this. Yes, many of them are supposedly fully submersible, but I prefer to keep the temperature control and cord above the surface, thank you. If you think about the mechanical linkage going from the knob down into the heater..... it's just another seal that could easily be compromised over time.

[mark]

don't believe dropping one meter lead into the tank and grounding the other will give much of a useful reading. I'd trust a GFI to be a more reliable indicator to show problems.