What the voltage or "current" can do to your fish is possable HLLD, kill you fish and corals, and generally cause strange behavior..ie rapid jerky swimming patterns, quivering things like that. The fish have an organ that is called the lateral line complex, with which they dectect changes in the area around them like water movment, other fish, navigation, locating food. They can also dectect stray voltage or electrical current.
You test stray voltage with a voltage meter. They can run 20 dollars on up. You need to turn the voltage meter to the 120 AC Voltage. One end of the probe "black" goes into the ground on a outlet like the screw to the plate of the outlet will do, make sure that there is no paint or dirt on it. The other end ofthe probe the "red" end goes into the tank. Then watch the digital numbers or needle move. IF it does move then you have voltage in your tank. This is nothing new so no one need panic at this point.
Now you need to write down the voltage reading. Lets say you come up with 25 volts. Then start disconecting your electrical equipment one at a time. When the voltage goes down figure the difference and write that down as well, so if you unplug the heater and the voltage drops to 12 then your heater was giving off 13 volts alone and should be replaced, I have had that happen on a glass heater, and replaced it with a won pro heat. do this for all electrical equipment and replace as nessessary.
Does this mean that you will read 0 volts...NO Saltwater ions flowing will actually generates an electrical current, this is why some will say that ALL tanks have stray voltage.
Voltage enters the tank by several means, one of which is called induction which is the process by which an elecrtic current, or electric charge, or magnetism is produced by the proximity of an electric or magnetic field...ie powerheads other water pumps. If you use fluorscent lights they will have a strong electric charge inside the tube, and bubbles that break the surface of the water or fish that splash will spray saltwater and if that comes in contact with the lights it could provide a path right to your tank just like sammystingray was talking about I believe. Thats happend to me too.
It is important to note that even if you use a ground probe that you must as a matter of routine maintanance pull the probe out of the water and test your voltage with a voltage meter.
I do know that when I built my ground probe (which cost me about $3.50 to make) I no longer had the problems that I was haveing.
I'll be open and honest
Stray voltage is something that I still do not understand enough. When I get to discussing it with person with an electrical background I find it hard to understand them simply because they are talking a different language to me, but I'm still trying.
I have several links about stray voltage if anyone needs them.
Thomas
