- Where is your thermometer? if it's on the glass.. it's only giving you one reading. In light of that, the rest of the tank, like the center maybe cooling down more with out the heater at night. Maybe this is beneficial for a bacteria bloom like the others said. I usually associate bacteria like plants, and would imagine they require a seasonal or night and day temperature variance that the heater does not allow. Although i don't know if it could explain the "debloom" happening with in hours of reinserting the heater. Just a thought i guess....
- Good Luck, and post anything you find for future reference
- AB-