Stray Voltage Question

perfectdark

perfectdark

Active Member
Ok so I have been trying to solve the mystery of my tank. Its a 29 gal cube with 2 submersed power heads and an upgraded return pump. In the last month I have put 2 fish in my tank and both had died. One died in 3 days the other less than 24 hours. All water chemistry spot on, RBTA thriving and has been for 8 months. One theory was stray voltage, I tested it and now my question is how much is too much voltage for a tank? I mean when should you be concerned that there is an issue. I read that there is always going to be some stray voltage in your tank. But no actual numbers have be shown. Mine tested at almost 5 volts, is this too much?
 
ameno

ameno

Active Member
My old tank had stray voltage all the time, can't remeber how much but it was more then 5 volts, had to be sure and not be grounded when sticking my hand in the tank are you would get a jap. finaly after breaking in down I narrowed it down to a couple RIO pumps, but the voltage never effected any of the live stock, I think it's like the bird on a wire effect, as long as the tank itself is not grounded the livestock would be ok, I have had fish die for no apperent reason before, anytime I buy from a certain LFS they usually don't make it, something about his water cemistry they just don't acclimate, I think. could be they were already not in the best of shape and the stress of the transfer finished them off, I know it can drive a person nuts trying to figure out what's up, but you might try another supplier and see what happens. may not be your tank at all.
 
perfectdark

perfectdark

Active Member
Originally Posted by ameno
My old tank had stray voltage all the time, can't remeber how much but it was more then 5 volts, had to be sure and not be grounded when sticking my hand in the tank are you would get a jap. finaly after breaking in down I narrowed it down to a couple RIO pumps, but the voltage never effected any of the live stock, I think it's like the bird on a wire effect, as long as the tank itself is not grounded the livestock would be ok, I have had fish die for no apperent reason before, anytime I buy from a certain LFS they usually don't make it, something about his water cemistry they just don't acclimate, I think. could be they were already not in the best of shape and the stress of the transfer finished them off, I know it can drive a person nuts trying to figure out what's up, but you might try another supplier and see what happens. may not be your tank at all.


Yea I did that both fish were from 2 different places. The second one was quarantined for 2 weeks too. And thats the one that didnt last 24 hours.
 
lmarc78

lmarc78

Member
Testing stray voltage can be a pretty tricky thing. Volt meters tend to give a low reading so with that said there is'nt really a good way to check for stray voltage. First thing you would need is too find out if the voltage is from you elecrical ground or from the tank. What can happen in older houses is the eletrode the electrition used outside of you house for grounding can erode or loose resistance from your soil. If thats the case plan on spending some extra money for a new electrition to come out.
If it is your tank you can buy a grounding device made for tanks that sits in the water . The instructions say to place the opiset side outside in the ground. I would ground it to the electrical box.
What I would assume off hand is that you voltage is really around 9-10 vlts. Enough to put lots of stress on a new fish.
 
scsinet

scsinet

Active Member
The problem is that a multimeter can pick up voltages induced by eddy currents. Eddy currents are currents that flow in a conductor that is in the presence of an alternating magnetic field. Saltwater is an excellent conductor, and ballasts and pumps are wonderful providers of magnetic fields.
There are ways to accurately test for stray voltage, but it involves loading resistors and other crap that gets complicated. A far easier way is to forget about testing for it and just prevent it. The way to do this is with a GFI and a grounding probe. By placing your equipment on a GFI and placing a grounding probe into your tank (properly grounded of course), you'll be good to go. The GFI won't trip from eddy currents, only a true fault, so as long as you have that setup, and the GFI isn't tripping, you're good to go.
 
tsdid

tsdid

Member
If you buy a plug in GFI and then plug an extention cord into that. It will detect all current correct?
 
tsdid

tsdid

Member
the other question i had is if you buy a titainium ground probe and that pulls voltage wouldnt that trip the GFI?
 
tsdid

tsdid

Member
the other question i had is if you buy a titainium ground probe and that pulls voltage wouldnt that trip the GFI?
 
tsdid

tsdid

Member
sorry I accidentily sent the message again. But if the point is to have a GFI for safty and the probe to take the current out of the water woulnt you not want the gfi to trip all the time.
 
perfectdark

perfectdark

Active Member
Originally Posted by tsdid
http:///forum/post/2531516
sorry I accidentily sent the message again. But if the point is to have a GFI for safty and the probe to take the current out of the water woulnt you not want the gfi to trip all the time.
Tripping the GFCI tells you that there is somthing faulty in your equipment. The idea of the prob is to direct the elec current to it rather than potentially hurting your inhabitants. If you have enough stray voltage to trip a GFCI you should find the source and eliminate it as I believe that is an excessive amount.
 
scsinet

scsinet

Active Member
Originally Posted by tsdid
http:///forum/post/2531516
sorry I accidentily sent the message again. But if the point is to have a GFI for safty and the probe to take the current out of the water woulnt you not want the gfi to trip all the time.
GFIs only trip during fault conditions. Merely operating a piece of equipment submerged in the water will not cause them to act. Only if somehow a live terminal would have to come into contact with the water would there be a problem.
 
You must log in or register to reply here.
Top