YVW, So the heat pad has a dial thingy on it? You may end up with high humidity (depending) inside the tub if so you can make a few air holes at a time, I prefer to use the tip of a hot glue gun, works fantastic. For a temp/hydrometer, most ppl that use a single tub setup get the accurite digital hydrometer/temp from wal mart in the neighborhood of 11 bucks or so.