I am new to frog caretaking, but all of my research suggested that for a Giant Pixie Frog all I would need for my 15 gallon tank would be a medium heat mat on the side of the vivarium. I have the heat mat placed on the shorter end of the glass vivarium (it had previously housed fish many many years ago). Inside I am using a coconut fiber substrate on half of the viv and a plastic water tub on the other half. The heating pad is on the end away from the water. It does not seem to be affecting the ambient temperature inside at all, and while it is warm to my touch, it certainly isn't hot. I tend to keep my house in the mid 60's in the winter. Could I have a faulty heat mat or do I need to look into some other form of heating. I have covered the top (my frog hasn't arrived yet) and that doesn't seem to help with increasing the temp either...