I lost power on Monday at 11:00pm and it came back on at 9:00pm Tuesday. My tank with two clownfish and an anemone got down to 65 degrees. Thankfully they all survived and look great now. On top of that I got a bounce mushroom in the mail Tuesday at 11:00 am. So I had to wait 8 hours for the power to come on and the tank to heat up before I could acclimate it. I was worried but it was 78 because of heat packs, and looks great in my tank. Nothing like a stressful start to the New Year.