stray voltage help

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Bige

Aquarium Advice Addict
Joined
Jul 3, 2009
Messages
1,699
Location
Austin,tx
How do you know if you have stray voltage? Should there be any? I ask because I put a voltage meter on my tank and it showed .3,.2 and went up and down. Should I get a probe? How exactly do you test your water? What should I ground the negative on voltage meter to?
 
What setting were you on when you got those readings? AC or DC? What I did when I read my tanks was use a paper clip to extend my meter leads (my leads are dirty) and for the ground, I stuck it in the third prong of the outlet. If you are worried about sticking the meter in the outlet you can just touch it to the screw that holds your outlet cover on.

Were you getting .3 volts or millivolts? What kind of meter are you using (Make/Model)? I run our calibration lab at work and deal with this stuff all the time.
 
I use it on my car so DC. On dcv setting on 200. It is a UEI dm 383 digital multimeter. I can post a pic if that helps. So if used on a car with same setting, car would be 12-14. Tank showed up as .3 and did not sit still. Up and down. Highest was .3 but it would cycle to 0. I did it after lights were off so I will try it now lights and pumps are running. Ok now using same setting, the meter moves very quickly between .3, .2, .1, oo.o.
 
I know our meters here at work will bounce around even when not hooked up to anything. Usually it is just tenths of a millivolt though. You can check your meter by shorting your leads together. You should get a reading close to, if not exactly, zero.

If you are really worried you could unplug your equipment from the tank for a little and take another reading with nothing running. If it bounces around still then it is most likely your meter.
 
The meter stays at zero with leads together. Good idea unplugging everything. I will try that tonight. If I get a grounding probe, anything special needed to connect it? Best placement?
 
To be honest, I've never seen a grounding probe for an aquarium. I'm assuming it will either have a ring tongue on the end or just a plug with just the ground prong on it.

Edit: I just googled grounding probe saltwater and found some Titanium probes on MarineDepot.com, it looks like they all have typical plugs on the end, the line and neutral prongs are just plastic - the only real prong is the ground.

I'm guessing hide it in a corner of the tank or something. I'll let the salties answer that one for you.
 
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Ya I have my ground probe in the back corner of the tank.. Dont think there is any special trick to em just make sure it touches the tank water.. either in sump or in the DT..

Shane.
 
Some people swear by ground probes, others not so much. We all agree, however, that a GFI circuit is a necessary safety measure.

That aside, I was going to recommend what Steve said. Turn everything off (unplugged) and see if you still see the jumps in your meter.
 
I have a ground probe in my Sw tank. Had for 13 yrs now. Soon to get the GFI circuit thing.
 
So with everything off, volts 0. So I got a grounding probe. Once installed, 0 volts. So now I can get on with things.
 
I checked all the equipment and couldnt find anything that was putting out the volts. So I decided probe was cheapest option. Will test again tomorrow.
 
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