I put my little guy in a tub (but not in a rack) and I am having some trouble keeping the temps stable. I have a hot hide on a mat with a therm. and my temps are great-ish there, but my cold side needs some work. I raised the room temp to 74, but any more than that will KILL my electric budget. What I did was put the top on and put 3 small holes over the cold side and set up my heat lamp about 6 inches above those holes. I bought an acurite temp thing, but where do I sit it? My temp gun says that under the heat lamp holes gets to 93, but not sure if that is even accurate. Would you put the acurite under those holes or on the other part of the cold side to get the most accurate temps? What do you suggest?