Just got zapped hard!
 

So im holding some good live rock for my new build. Lots of life etc. 2 tanks with a powerhead, a heater and a small HOB filter.

Today I went to touch the water (as I always do to make sure that my thermometers are accurate). And it felt like someone punched me in the chest! Got it bad enough to knock me on my a$$.

So im thinking heaters, as these are the common culperits. Im kind of scared to test my theory though. Dont really want to replace the heater and try it again lol. How do I test for voltage without killing myself?

And the big question...now that I know this is happening....is everything dead in the rock now? Or would the current not harm bacteria etc?. I havent gone back out to look for pods etc.

I use a Fluke pen to test for A/C voltage on wires. It looks like an a fat plastic pen that just needs to be close to the current and then lights up if there is power there. I haven't tried it in water though and without purposely adding electricity to my tank I can't say for sure if it works. They are cheap and other companies besides Fluke make them. They come in handy for wall receptacles, testing extension cords, etc. If you know any electricians they would be likely to have one to try.

I would get a grounding probe. They are fairly cheap.
I had a similar problem turns out it was my skimmer pump cord. It was wearing.

using a gfi?

Get a cheap multi meter, stick the black end into the earth pole on a three prong plug, put the other end in the tank. Get a helper to unplug things one at a time, when the voltage drops to zero the last item unplugged is the culprit. Good luck.

Edit:
When a heater went bad in my display I had the same shocking experience, I didn't notice any damage to the livestock in the tank. The fish were a bit skittish, but no harm done. The fish that were in there are still in there after about 2 years.

holy frak! Glad to hear you're ok! Would hate for you to have yet another excuse not to finish your build.

All kidding aside, keeps us updated on what you find! You've got me scared to put my hand in my tank now!

remember that fish in the tank are not grounded.....

when you reach in, you probably are grounded and the current travels through you.... & thats what hurts.....

I've often wondered why Neptune hasn't made some kind of voltage detector for the Apex. Or any other controller manufacturer...

Hmm.. maybe I should make something.

It really is as simple as having a voltage meter in the water and then the other end to ground. It could monitor the voltage in your tank.

FWIW you'll always get some stray voltage in the water. It is when it gets high that it is a problem. And yes - I know.. it is the current that kills you not the voltage... Either way - some way to indicate that it is safe for me to put my hand in the water.

Glad you survived. The most I ever got was an uncomfortable tingling. Found the heater that was the culprit.

I have a multi-meter. Would that work if I dipped the ends in the water?

LOL!!!! No excuse...YET. I'm still kickin! haha.

After work today I'm going to take the heaters out, and inspect all the powerheads as well. See if I can find anything obvious.