well what is the temp of the room that your snake is in?? that could be affecting it. I always keep a towel over the top and a small thin blanket over half to make sure it stays around 80. how big is the heat pad that you have in the middle of the tank?? it should be at least 1/3 of the bottom and if it's too small then that could have something to do with it too. other than that I don't know. High 70s is still okay...as long as it doesn't go below 75