So I have a 200 watt heater for my 20 long, and even though I have it set at 82*F the tank temp is only 72*, and more than likely that is room temp. I was wondering if there was some special way i need to calibrate it. The way I thought you were suppose to isn't working. She got it off of eBay about 5 months ago and my wife used it in her 10g F.W beta fry tank and it worked perfectly but now it won't keep temp. It is a chineese brand called jbr I belielieve. TIA and happy reefing.