My heater is miles out. It's set at 22C (72F), and always sits between 27-28C (81-82F) which is top of what my fish can tolerate. I've just walked into my room and found it at 29C (84F), so I've turned the heater off and opened the lid to let it cool down. Problem is, I'm away all week and can't keep an eye on it. I've turned it down slowly since purchasing it, yet the temperature has always stayed around 27-28C. So what d'ya guys think i should do? Put it on the lowest temperature, and sort it out with my LFS at the weekend?