I have just purchased a baby veiled. I am aware that the enclosure I have now is to small but i am building a cage within the month. My problem is that I bought a 125 watt uva/uvb light and yesterday it was registering at about 105 - 110. I moved it back a little and now it is saying anywhere from 120to 170. Is this a malfuction with the themometer or what? any advice?