just a comment on the plug in GFCI adapters. These only work if the outlet itself is actually grounded. If your outlet is a two prong outlet, do NOT put a 3-prong to 2-prong adapter on the GFCI adapter. That thrid prong is the "Ground" and the Ground F
nterupt needs that in order to work. If your wall outlet only has two prongs then you quite likely have old wiring (I'm not knowledgeable enough to estimate any timeframe) but if you have a two prong outlet, I would seriously consider a new circuit for your tank.
, I tend to be paranoid