the big hole in the side is probably why it wont hold water idk without having a good gander at it, but it may need some kind of gasket around the bulkhead fitting.
yup, absolutely pure water will not conduct electricity. that fact will blow most peoples minds. many moons ago i was an interior communications electrician in the navy, i have some stories.
thats how i roll, no heaters in my tanks. i have them for emergency use, but do not use them. tanks tend to stay a few degrees above room temp also with heat from filters, air pumps, lighting etc.
when you thought you were good, flip the little lever and make the paddles tiny. space invaders etc, all the original atari games were fun. they may not have looked very good, but they were fun.
you can probably get away with it, with 10 gallon tanks. i however would never attempt it as i just dont trust glass, and silicone when you add in a torsional stress.