I saw no one had answered you so I thought I would help. You should be fine for that length of time. If you need to keep you tank warm you can heat water and fill plastic bottles and put them in the tank every couple of hours or so. Or wrap the tank in a blanket or something to hold the heat until the power comes on. You can also stir the top of the water every so often to help oxygenate it. You can also take a gallon jug, fill it with water, then hang it over the tank, you then punch a hole in the bottom of the jug to allow a drop of water to fall. The dripping water will help agitate the water and keep oxygen in the water. It works pretty well.