yeah that is a lot of juice. maybe you have a huge tank or it could be a little overkill. one of my smaller tanks last week went up into the low 90's for most of the week and i failed to notice it. i was in the process of a big move and the tank was not at full capacity. the lower water level allowed the heat to increase by 10 degrees. i was shocked when i looked at the thermometer. luckily no fish were killed, but it scared me. def keep an eye on the temp. until it stabilizes.