@ADsnail,
I live in Southern New Zealand, so very cold , the lowest temperature the tropicals got to was 11C , , they had stopped moving , and were not happy, i dont think they would have lasted another few hours . On that specific horrific occasion 20 hs , I had covered their tanks with blankets after I got home from work , I didnt check the temperature till the power came back on , so I dont how long it took to get that low , or how long they had been at that temperature ... but the power had gone off just before leaving for work , I got home about 12 hrs later , power still off so I guessed was a big hard to find issue for the power lines guys. Hence covering the tanks with duvets etc, but that was the only time I did cover the tanks , and i put duck tape on them to hold in place lol