| | Re: Shocked by my plastic marineland heater
You can also install a GFCI receptacle on the outlet feeding the aquarium. They're no more difficult to install than a regular outlet although they do take about a 60% more space in the outlet box.
Most states are starting to adopt the 2008 NEC and just about all the GFCI's sold these days have to meet the new code. If you can find an "old style" GFCI outlet at your local electrical distributor, you could probably snag it cheap. There's nothing wrong with it - it meets the 2005 NEC requirements - it just doesn't meet the current electric code. I put several the rent house I'm living in and they've saved me from myself a couple times!