Has no one ever thought of putting under floor heating mat under your insulated tank for the winter.Another thought on a visit to South Africa I called on a Home show and saw a under carpet and floor heating system made of a type of nylon fibre net to promote this product ,they had it in a glass tank of water. The water was boiling in this glass tank.The elactric leeds were outside of the tank.This my friends might be the solution to frozen water tanks and producing warmer water for winter.