Aqua Medic Temp controller

[banditpowdercoat]

I reciently got a Aqua medic Biotherm Temp controller and 250W Titanium heater from Wendell @ OA. read way to many horror stories about glass ones breaking etc. Well, the first one was DOA. Temp just kept climbing and climbing. This replacement seems to be heating too much. Temp is set at 78, but goes to 81.X before shutting off. Getting a 4* swing. Is that OK? Or to much for fishies? Did I waste my $$$ on this controller?