I own a 2013 Hot Springs Grandee and ice is building on both sides at the "hinge" in the middle. The ice starts at where the cover meets the tub and builds bigger and downward towards the ground. How should I compensate to eliminate this problem? My fear is the ice will continue to build and damage either the spa shell or the exterior. Any advice is appreciated. Daily temps have been aroung 15 degrees here in Upstate NY...