Dealing with a stressed fish and I think the heater may be the cause. My girlfriends Dad gave me his Surpreme Heetmaster Model 2. It is in working condition the only thing is that it doesn't have a temperature gauge like the new heaters. It has a knob on the top with numbers on it. I know these things used to be pretty popular anybody know anything about this? Google brought up zero results so any input is apprecitaed.