Recently had a heater stop working. The water went really cold as we are in the middle of winter here. I have heard that some people put 2 heaters in their tank in case one fails, the other will take over. Any one do this? Does it really work? What is the best way to do this....use 2 of the same size heater or set them one at a bit lower degree than the other and it just sits there in the tank 'just in case' ? Thanks for your advice.