I do have an under-the -tank heater. It keeps things at a consistent temperature. We had fifteen degree weather with straight line high winds. Things got cold, quickly, changing the overall temperature of the room. I live in an old farm house with old windows and mediocre insulation. Helene wrecked my setup by loss of power. Wanting to start an ecosystem again, I am starting with the hermit crab. Ive increased total room temp and weather has eased off. The warmer days may bring them out of molt. Im "fixin to" do a good cleaning and wash things. Areate the sand, other than the sand under the coconut shell Quanset-hut getaways Ive made. They chose to pile sand up, completely blocking the openings. I know I saw one out of its shell but it still had slight movements and there has never been any smell of death. With the greatest of ease, I manipulated the crab into a different larger shell. Same shape and color. I want to eventually have a complete ecosystem. Marine salt water to dry sand land plants and animals. A marine Cephalopod(octopus) to a land arthropod(fruit fly) setup. Being at risk for power loss intermittently, I have started back with creating the land section first. In the spring, I can rely on more suitable weather to help me get it right. I will keep the forum posted and report any significant changes. Bachelor of Science degrees require alot of experiments, give and take, and consistent, detailed documentation. Any advice is accepted. Im happy to be back "reefer-ing". Don't get me started on that issue.