tundra, I am among those who could no sooner build one of these than I could read a page of programming code, but I would like to thank you warmly for undertaking and persuing it. My tray temps vary significantly, season depending (my tanks go in water baths), and I would love to have such an item. I have not sprung for one of the commercial ones, due to cost-justification. That you have updated the Zone VI one will surely be welcomed by many, and perhaps, copyright understood, there will at some point be a future for some production of them, or perhaps people like me will find others willing to make one for a reasonably affordable compensation -- compensation for compensation!