Shock in Aquarium - GFCI Outlet?

Chrysus · Jul 30, 2025

I’m finally getting back into the fish keeping hobby, and reviving some very neglected tanks. I’ve been doing a series of water changes and had two pretty significant shocks over the weekend, and probably several minor ones. One was on the screw in the bottom of the python water changer (20ft away from the tank!), and the other was on the actual power bar (which has a metal housing) when I put my hand on it to unplug a power head. Using a multimeter I think we narrowed it down to the two power heads - we placed them individually in a bucket, plugged them in, and got a reading from the water of just over 50V for each. Am I correct to think that is not normal? Does the water movement impact it at all? It just seems a bit odd that they’re equally faulty. They’re both Fluval CP3s.

I’ve read some of the posts on here and see the recommendations for grounding probes and GFCI plugs. The GFCI plugs often seem to be one outlet - does it work the same if I plug a power bar into one? I’m replacing the power bar as well, but need 8 outlets. I know very little about electricity, except that it is quite unpleasant! :)

JumboShrimp · Jul 30, 2025

I like these, from Amazon.

W31Olds · Jul 30, 2025

If they are AC Power Heads they probably not your problem. GFCI outlets work even if you have your entire tank plugged into it. Take a look at the condition of your heaters and return pump, and salt creep say on your power bar. JumboShrimp's choice is on point.

Chrysus · Jul 30, 2025

W31Olds said:
If they are AC Power Heads they probably not your problem. GFCI outlets work even if you have your entire tank plugged into it. Take a look at the condition of your heaters and return pump, and salt creep say on your power bar. JumboShrimp's choice is on point.

The tank runs a canister with a heater in it, which was fully disconnected/taken apart at the time of the second shock. During the first shock heater and filter were unplugged. Just HOB, power heads, and lights were plugged in. I had thought it may be the power bar itself, but that wouldn’t explain the shock at the sink the first time. Pump and heater for the saltwater mixing station were plugged in the second time. Maybe I have more than one issue!

I’ll get a GFCI outlet for sure, I’m in Canada so not sure if I can get the one linked but I’ll look for something similar.