Dude, don't screw around with electricity and water. If you feel any electricity, find that problem. I'm not kidding, your life could depend on it. Electrical problems don't get better. They get worse. You don't want to wait until that happens.
Why are you heating your water? The air stones and light should do the trick. Air pumps produce heat and release some in the warm air they put out. The water
pump should also be producing heat. It could also be a part of the problem if you have any exposure.