Originally Posted by Asphenaz
Wow, I'm glad all you got was a shock. I would second the recommendation of at least a GFI power strip.
It's connected to a surge protecting power strip. I'm guessing that the resistance of my arm was still high enough that the current wasn't seen as a ground fault. In this case a GFI may not have helped anyway.
Originally Posted by JERP
Test each outlet connected to aquarium devices (incl. light) to make sure that the earth ground and the hot and neutral are correctly wired. Device grounding doesn't help if it's not connected at the outlet.
I tested all the outlets afterwards. I originally thought the light was shorted as it was new and that something was wrong with the ground line. After the light case, and the outlets checked out ok, I realized that there was something shorting to the water, and I just grounded it to the light with my shoulder. Testing from water to ground with a voltage meter confirmed that something was fully shorted into the water. Never would have thought the plastic heater would be the problem.