well they are only $75 or so but require a controller, i love my controller with 2 1000 watt heaters, took care of my heating problem. i tried the multiple 300 watt heater option, i had 5 ebo jager 300 watt heaters and didn't heat worth a crap in my opinion and the thermostats were always coming on and off, had to always adjust etc. i love my jehmco/controller setup.
Yeah I don't think it's going to be cheap to keep the tank heated enough through out the winter without proper planning. How much did you spend on your setup? It really sounds amazing...