I've got a tank that has the small unit on it. I had a hard time finding a decent heater for the small one. I was hoping you might have already had some luck with something that you could recommend to me
, but I guess my little hang on will have to work for now. Tronic and visitherms didn't fit and I'm not sure if a titanium heater would be safe for the gasket. Let me know if you find something that works for you.