A couple of weeks ago, with the temperature well over 100 degrees, we experienced a major power failure. The longest we had previously gone without power was three hours.
I tracked the effects on my tank temperatures. The most important factor was that the house air conditioning was set at 71 degrees, and being reasonably insulated, it took a long time for the house temperature to rise. At the end of 10 hours it was 83 degrees. The two tanks are kept at 77 and 78 degrees. After 8 hours, the temperatures had risen to over 80 degrees, so I floated a quart bag 1/3 full of ice cubes in each, and also added a small air pump with bubbler tip. (I have no cephs in my tanks right now - just corals and fish. I couldn't use a bubbler with octopuses). Anyway, that was enough, and the tanks came through this ordeal in perfect shape.
Nancy
I tracked the effects on my tank temperatures. The most important factor was that the house air conditioning was set at 71 degrees, and being reasonably insulated, it took a long time for the house temperature to rise. At the end of 10 hours it was 83 degrees. The two tanks are kept at 77 and 78 degrees. After 8 hours, the temperatures had risen to over 80 degrees, so I floated a quart bag 1/3 full of ice cubes in each, and also added a small air pump with bubbler tip. (I have no cephs in my tanks right now - just corals and fish. I couldn't use a bubbler with octopuses). Anyway, that was enough, and the tanks came through this ordeal in perfect shape.
Nancy