12 v tank heater

I recently added a wind turbine to my PV system and it came with a large resistor as a load dump  to simply dissipate energy produced after batteries are fully charged. So my first thought was why waste electricity that I paid to produce? If I were to add a 12v deicer to the system for my 3000 gal water tank just to take the edge off of the  -12 winter in northern az, and kill 2 birds with 1 stone. A 12 v floating deicer would be ideal, but I cannot locate any such item. Floating deicers seem to all be 120 v, which seems like a good way to kill some livestock, and would require a dedicated inverter. The other option is 12 v submersibles, which screw into stock tanks, but that would require a 1" bulkhead near the tank so the element would never be dry, and I am unsure whether that would be possible without impacting the integrity of the tank, or where to even get a bulkhead that would work. Anyone.....Bueller....any advice would be greatly appreciated.  stay safe