Wiring advice/help needed (voltage in tank)

[Wildechild_01]

Originally Posted by Vancity

TEST #1
So + in tank, - in ground on GFCI (This time i plug in each device and then unplug and move to the next one)
2.7v w/nothing
T5 Lights = 4.6
Koralia = 15
Aquaclear = 9.5
Skimmer = 20.6
Heater = 22.0

w/nothing = salt water is an electrolyte it gets used in batteries to generate electricity, depending on what else is physically in your tank this could be what is happening and would explain why as soon as you remove the rid-volt you read the small voltage being generated by the system itself

T5 Lights = Magnetic Ballasts and fluorescent lamps - generate magnetic fields, this will create an electrical charge when the magnetic fields interact with the salt water. Voltage is created but it is not "leaking" from the fixture into the water. Smallest offender (now that you have properly grounded the ballasts and fixture) because magnetic field needs to cross air gap before getting to water so weaker fields interacting with water. When the fixture was not properly grounded all metal parts of the fixture would have had some induced voltage in them as well now those induced voltages can go to ground safely rather than messing with the tank even more.

Koralia = Motor = spinning magnets. Spinning Magnets + salt water = more generated electrical charge again without actually leaking voltage from the equipment.

The above applies to everything with a motor so skipping to....

Heaters - This is probably the most likely to actually be leaking voltage, if it was actually leaking voltage though i would expect the GFCI to trip when you use the rid-volt. Heaters however operate by running electricity through a coil of wire designed to conduct a little poorly and heat up. Now you have a coil of wire with alternating current running through it, without getting too technical this also results in magnetic fields being generated they expand and contract moving across the conductor that is the salt water, again voltage will be generated.

Checking my tank I sit around 60v, a little higher than yours but if i remember correctly you said your set up is 90G, the water can only hold a certain amount of charge (like a battery) my 125G would then be able to hold a little more. adding a ground probe to my tank also drops the voltage to zero with no measurable current ... okay full disclosure i managed to get a 5 microAmp reading with my "i don't want to talk about what i paid for it" volt meter. with no measurable current flowing probably safe for fish to leave probe in.

Originally Posted by Vancity

hmmm, all my equipment appears to be faulty now?? Is it at all possible that my un-grounded T5 issue from 2 weeks ago could have caused other equipment to slowly break down the ability to not release stray voltage?
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Nope.....

My Guess is that there is nothing wrong with any of your equipment. The voltages you are reading are a result of Magnetic Induction. If you are getting a zero on current measurements then i say toss the probe in and be done with it. If anything does break in anyway and starts to leak any power the probe will then let the GFCI trip.

Aaandd... Bed Time gotta go play electrician super early tomorrow.... at least its almost the weekend