My enclosure is indoors...Livingstone said:The under tank heater will work but you will need to monitor the temperature of the base of the tank, not the water. The heat pad can cause a hot spot which would burn the feet or plastron. I thought about doing this for livingstones bath but even after 3o minutes the water had not dropped below 80, this is indoors by the way. If I was going to do it I would probably take the heat cable and wrap it around the sides of the tub, the heat would disperse more evenly through the water. Interesting idea though.