Stray Voltage
 

Hey guys,

My frag tank has a stray voltage of around 30. No one item has more than 6 but between my return, heaters, skimmer, ATO it sums to around 30. Is this a problem. I am not buying all new equipment as most of these items are barely a year old.

Why were you checking? Noticing issues or were you geting zapped?

Was seeing some of my LPS corals in the DT not expanding as much so I tested it and it was fine around 5. I thought while I am at it I might as well test the Frag tank and that's when I noticed it. I haven't seen any problems in the tank. No shocks.

Not super familiar with it but from what I was reading they don't seem to be concerned under 40v. How were you testing it? I am kinda curious now I know I had a bunch of stray voltage in one of my tanks before actually getting a shock found a bad ground inside of the outlet it was plugged into.

Voltage measured with a meter from a tank to ground is not necessarily an issue. It's when the voltage has a path to ground. This will result in current flow from the voltage source to ground. If something of lower resistance gets between the voltage & ground, that results in shock. Generally, if the electrics running your tank are plugged into a GFCI outlet, you'll be safe. While 30 volts is getting up there, there are many pitfalls when trying to measure voltage & current in salt water. If you're not getting zapped when touching the water & the livestock isn't acting weird, there shouldn't be cause for concern.

Thanks all. I am using a digital multimeter from the ground of an outlet to the tank.

My experience is that stray voltage is not good. I had a problem years ago with it. It wasn't enough to give me a shock but I noticed it when a cut on my finger was "buzzing" like putting a 9 volt battery on your tongue. I didn't measure the magnitude of the voltage but guessing it was under 20 volts. That was enough to cause slow death of corals and fish over several months. So I would be worried about it.

to be honest, I never really thought about it but, with all of the equipment in a small space the possibility is always there.

I installed a $9 grounding probe I picked up in a recent order from J & L. I just grounded my sump, not the display tank since it's just a holder of the water and nothing is submerged on the DT.

I will not add a grounding probe to my tank. I value my fish over myself :)

There's an abundance of info out there on the subject of grounding probes/stray voltage. Bottom line is, protect yourself by ensuring any electrical equipment associated with your tank is on a GFI protected circuit and if you have any doubt about a piece of equipment, even if it's relatively new, replace it. I value me, family & friends over my fishies.

GFCI should be manditory piece of equipment. A grounding probe in conjunction with a GFCI is a good idea for added safety.

40volts is a lot. Some small voltage is expected and can simply be induced by properly working equipment being submerged in water. But seeing voltage at 12v or higher I would be very concerned myself as that is going to be a good sign that a piece of equipment is open or shorting. Some of our powerheads work on these 12v-24v low levels of DC voltage but that amperage on short can definitely lead to livestock problems.

Everything is on a GFCI and its only 30 volts. No one device shows very high so I don't think I have any equipment failing. Maybe I will do the whole process again to see exactly what voltage each device is giving off. Again most of the equipment is fairly new.