A few days ago, I gave myself a small papercut on one of my fingers. I don’t think there are many positive attributes with a paper cut. But yesterday, that same paper cut clued me into some stray voltage in my reef aquarium. I was doing a water change on my tank, and felt an immediate stinging at the site of the papercut. Now, we all know salt water will sting a cut. But it usually goes away quickly. I remembered the last time this occurred, it was due to a small amount of stray voltage. It was not something I could feel with the hand that didn’t have a cut on it.
I promptly pulled out the multimeter to verify my findings and isolate the source. It turned out to be a powerhead that feeds the calcium reactor. Unplugging the powerhead brought the voltage down on the multimeter, and the stinging sensation in my finger was gone. I guess it’s time for a new powerhead.
I don’t advocate using your hand to test for stray voltage! But if you feel a sting or tingle in a papercut or hangnail while servicing the tank, it would be wise to test your tank with a multimeter. To test for stray voltage, insert the black probe into the ground port on an outlet or extension cord and the red probe in your tank. If the meter registers voltage, then you should proceed to disconnect each electrical device until the voltage drops. If you disconnect each device one-by-one, the culprit is easily found. Multimeters are pretty cheap and can be found at any home improvement store.
I also recommend getting a grounding probe, and investing in GFCI outlets. While the stray voltage I found was not life threatening, there are cases when a GFCI could save your life.