I just got two baby Leopard Geckos and I only have a Zoo Med heat rock for them to use until I can get a under-the-tank heater in a few weeks. Will this be too hot for them? It's new and it worked fine for our beardie, I used a temp gun on it and it was 100 degrees. I do have a heat lamp to use during the day, but i'm worried about them being cold at night when I turn the light off.