So I just set up my new 40 gallon aquarium and I put my heater in (aqueoun 150w adjustable) and set it to 76. I have a digital thermometer with the probe inside the water and the prob is reading a constant 81-82 degrees. The thermometer strip on the outside also reads 82. I unplugged my heater to see if I could cool water down then plug it back in but it's not going down. My living room is not 82 degrees and no direct sunlight hits the tank to my knowledge. What is going on??