Eheim Jager heater problem?

Sessomaru

I have a 300 watt Eheim Jager heater (with the red and blue dial). I've had it for about 9 months and within the last week it went from holding its temperature of 80 degrees and then dropping to 74-76 degrees. I've tried recalibrating the heater and it still didn't change the temperature. I've also tried turning the heater up to 85-86 but the warmest the tank gets is 77 degrees.

I have a 180 gallon aquarium.

I've tried emailing Eheim but they just resent the instructions to recalibrate (which I have) and they mentioned ambient room temperature changes as well (it's about 76 degrees in the room that the tank is in)

Any help is appreciated!

Romad

Is that the only heater in the tank? With a tank that size it's best to have two - one on either end (ish).

I've got 2 in my 75 gallon but it gets frigid here in the winter and we keep the heat down to 60 or 65 overnight.

AbbeysDad

I have two (200w / 250w) in my 60g.

I also think you should add another 250w or 300w heater.