I just had an image of the tank full of dead fish. We have always used the simple slap on thermometer to gauge the temp of the tank. We used to have problems with our 55 gallon tanks heater. It was just poorly made and kept shorting out. I would suggest following Provs advice without the fish in it of course. :wink:prov356 said:I've had heaters that weren't calibrated well, so I'd just turn them up, but that's playing with fire, and I eventually replaced them. Your only other option is to keep turning it up a little bit at a time until it keeps the temp where you want it. If it's clicking off at 75, but set higher, then definitely faulty. If it were me, I'd replace it, as they're not that expensive. When I get tempted to cut corners, I usually just picture a tank of dead fish, then I'm online ordering a replacement.
That is one that can be recalibrated, that's correct. I think that's the only one I've seen where that's possible. Because I was even thinking chances are that's not what this guy has, and sure enough...newforestrob said:this heaters been running like this for over a year,after posting my comment I did a search to order the same heater and found that it can be recalibrated,its an eheim jager tru temp,it has a readjustment ring,I'll take a look at it tomorrow during a w.c.