I have done it in a 10 gallon QT with a 300W unregulated titanium heater.
I would also shoot rather for 50 °C and do at least 2 to 4 hours - 24 would even be better if energy consumption isn't an issue.
In general this is something I would only do for smaller QTs with simple, strictly internal equipment, never for a DT with complicated external plumbing.