I have a 55 gallon tank and last night noticed my Malawi's were sluggish. Luckily this was a scheduled water change night. The heater (Marineland Visitherm 300watt) had failed. The light was on, but the water was 60 degrees (pretty sure it failed the day before). I shot down to Petco and picked up a 200 watt Aqueon heater. The manufacturer is sending me another Visitherm. Does anyone have a recommend of their own for a heater. I am also curious as to settings of the heater to compensate for a cold room. Any thought, tips or comments are welcomed. Thanks, Derek