Hi. I’m new here and would welcome some advice. I have a 6month old Russian Tortoise kept in a tortoise table. As it’s now getting cold at night and the Mercury bulb with UV goes off. I’m wondering what people use in the indoor part of their table to ensure it doesn’t go below 15 degrees at night? I’ve heard hear mats can be dangerous, but maybe having them on the side can be better. I’d welcome any suggestions on the best thing to do. Thanks