The replacement HE-CNTRL Thermostat assembly are used in all of the old style Brower Metal Units as well as the old style Pride of the Farm WE-5 and WE-4. This thermostat is preprogramed to turn on when the surrounding air is at 40 degrees and will shut off when the air is 60 degrees. Wire with your existing heater.
The thermostat is not designed for water submersion but should be installed as a replacement for the existing thermostat.