posted 6 years ago
It occurs to me that it might be partially dependant on the exchange rate for the tank. When I pump water in, its maybe 45 to 55 degrees depending on your deep ground temp. If I have fairly heavy and constant flow through the tank, I may well be able to heavily insulate the tank. If the water is going to set there with little flow through, there will be less heat coming into the tank, making the need for heat greater.