I think you should look into getting another thermometer--I've had some glass ones give me totally incorrect results.
Also, I don't know why you had so much trouble with your fishless cycle--a fishless cycle is no more or less complicated than a fish-in cycle. They're exactly the same thing except that the fishless version is faster, easier, requires less water changes, and doesn't harm your fish. This comment was more directed at Lion Mom. :) Sometimes I do end up doing a water change mid-cycle because the nitrites can really get up there before the nitrite-nitrate bacteria catch up to the ammonia-nitrite bacteria. You should only have needed a couple water changes--one to control potentially high nitrites (if they got near 8ppm) and one water change right before you put your fish in to get the nitrates down. More than anything I think your heater/thermometer issues have been frustrating you, lol. I haven't had time to read the entire thread, though.