I always turn off my heaters during water changes.
confused? pretty much all that you need to do for safety sake is push the heater to the bottom of the tank below were you are draining. I have blown one up in the past before i ever new better so i cant talk much. I allways place them side ways in my tanks now about a inch from the bottom. Slowly converting over to all in lines thow
Lol, that would of scared the hell out of me...luckily I've never blown a heater up yet...I did however leave one plugged in when I did a 50% w/c once and I smelled the smoke and I immediately unplugged it and realized my mistake.i forgot to unplug my heater once. sounded like a gunshot when it exploded