Makes a lot more sense now... Yeah, those are the probes I am talking about. Technically only need one, but I'm a fan of redundancy.
If you get a GFCI plug, be sure to test it. If it does not work on the outlet your tank is on, the ground may not be hooked up and you will need to address that for the probe to be any use. 99% of outlets are wired correctly, but some times someone is lazy and does not bother with the ground wire.