i would suggest getting a heater with internal thermostat and add an external controller like ink bird on top of it. Heater failure can cause the tank to crash, and its always nice to have secondary fallback/insurance. There is practically no price different for the heater with thermostat or the one without.
Very interesting idea here. Double protection. Would anyone be willing to give a 2nd opinion on this idea?
That should work, although the main component on the heater itself that fails is the relay that connects or disconnects for the thermostatic control. A heater with internal thermostat has a relay that could fail, while a heater without internal thermostatic control has no internal relay and is theoretically more reliable. Either way, it is probably a good idea to replace heaters every year to avoid failure. The added control redundancy preventing failure stuck on is probably well worth the risk of wear on an extra relay.
Also, if you use a heater with internal thermostat, make sure to set the internal thermostat to a higher setting than on the external controller.
...also, +1 on heater redundancy with two or more heaters. This is exactly why I have two Ranco controllers, one for each heater. If set a couple degrees apart, the back-up should never be used until event of failure on the first (hopefully fails off), in which case the back-up provides heat until replacement of the first unit. You could run these cyclically by waiting for failure of the first before replacing, using the back-up as the new primary unit and replacing back-up with new unit, and so on, though this is running a slightly higher risk of failure than just replacing the heater.
With redundancy, failure off for the primary heater is not an issue, but failure on (for either heater) would still be an issue, so replacement often is the safest option.
