Voltage in tank

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I have picked up a 185 mV (0.18 V) DC in my water column. I am battling to work out what is causing it.

Is this harmful to the tank inmates ?
 
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Careful there.....Dont go barefoot round the tank with your hands in or
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I read something a while ago about someone who had a very similar problem,they said it was an induced voltage caused by the pump motors and relative metal and magnets surrounding them.Im not too clear as to what they were saying exactly,but at the end of the day it started with a mV reading in their tank that couldn't be traced.I will try to find the article,unless someone else knows more!
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BTW I had a similar problem a little while ago and it turned out to be one of my powerheads which subsequntly packed up.Havent had a stray voltage again
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First suspect : pumps and power heads, second: fluorescent lights.

Check your AC voltage, it's possibly much higher...

Hennie
Cannot get an AC reading, either the meter can't go low enough or it ain't there.

I have tested lights and pumps individually.

Would an inverter be a possible cause ?
 
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You can't really just test like that, as its measuring the potential differance between the 2 probes in the water only, Try do a test by placing 1 probe in the water and the other on somehing that is earthed, perhaps the aluminium cover of a lighting hood (If you know its earthed)..... then you will start getting some true results....

BUT BE CAREFULL
 
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Cannot get an AC reading, either the meter can't go low enough or it ain't there.

I have tested lights and pumps individually.

Would an inverter be a possible cause ?
If you are running off the inverter or if using a online unit it may not have a Earth.
 
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You can't really just test like that, as its measuring the potential differance between the 2 probes in the water only, Try do a test by placing 1 probe in the water and the other on somehing that is earthed, perhaps the aluminium cover of a lighting hood (If you know its earthed)..... then you will start getting some true results....

BUT BE CAREFULL
OK, I have done it and I get a lower reading - 50 mV
 
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OK, I have done it and I get a lower reading - 50 mV

That shouldn't be problem, in other words, if you are standing on the floor bare foot with a hand in the tank, a voltage of 50mv would pass through your body if you were made out of a conductor like copper, but you not, so only a fraction of the 50mv will pass through you. you should be safe.:thumbup:
 
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How could one earth the water incase there is an earth leakage. We cant put copper in the tank.
 

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IIRC titanium bicycle spokes can also work well as a tank earther. But rather find the source of the leakage and stop it, a big (electrical) current in the tank can cause problems in fish, especially tangs (lateral line erosion)
 
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Im thinking more in terms of the earth leakage tripping rather than getting electrocuted should there be anything wrong and you are unaware.
 
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That shouldn't be problem, in other words, if you are standing on the floor bare foot with a hand in the tank, a voltage of 50mv would pass through your body if you were made out of a conductor like copper, but you not, so only a fraction of the 50mv will pass through you. you should be safe.:thumbup:
I only picked up there was a voltage because of a wound on my hand. I cannot feel it on my other hand.

My concern is my fish rather than myself, I know what 220VAC feel like and quick to get that sorted, it's these small voltage leakages that concern me.
 
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How could one earth the water incase there is an earth leakage. We cant put copper in the tank.
Make sure every electrical appliance connect to the tank has an earth connection. unfortunately this is not the norm.
 
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IIRC titanium bicycle spokes can also work well as a tank earther. But rather find the source of the leakage and stop it, a big (electrical) current in the tank can cause problems in fish, especially tangs (lateral line erosion)
Totally agree, earthing tank is not a good idea.
 
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How do you earth the 2 pin plugs. My pumps are all 2 pins, my heater, just about everything actually.
 
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How do you earth the 2 pin plugs. My pumps are all 2 pins, my heater, just about everything actually.
There is the exact problem.

Some pumps you can connect the earth wire to the actual motor with some minor mods. Heaters is not something, I have any idea about.
 
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I think its a good idea to earth the water somehow. Doesnt have to be to the earth in the mains. Can be connected to an earth bar thats pinned in the ground or something.
 
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Problem with that, is you will never know you have a leak and the fish will take the brunt of 220 V running through the water column 24/7.

Not good
 

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