We have a 20,000 gallon steel above ground water tank with winter temperatures reaching -20F degrees. Have been using agricultural water heaters, but this has been expensive and subject to heater failures. Looking for options and names of equipment suppliers.
Mssr. Billp..If you are in search of a long term solution to this problem, perhaps the following suggestion will be of some value. Construct a thermally engineered structure over or enclosing this tank with as high an R rating as practicable. If in your latitude and climate passive solar heating has merit, than it too might be considered in the overall plan. With a little imagination the outer configuration could be tweeked to reflect any aesthetic considerations for that locale. The co-generation of heat and storable electrical energy could be accomplished with a tiny little diesel generator in the event of prolonged cold weather. Many blessings on your family and may your oasis never freeze. Akmed..of de Nile