I'm sorry okay, I've put the right measurement of bark in and I understand now that it can't heat it but I was just panicking because I didn't want my snake to be too cold. I have defiantly put plenty of bark in now so she is safe. I really do appreciate your advice, I was just a bit stuck with too hot and too cold at the time. I will go down to my local reptile store where I know a guy that can help me out with the heating. I'm sorry and thank you for all the advise, I understand.