In addition to the gizmo you should pack the skimmer with something to allow ice to expand without doing damage. I use closed cell foam, eccofoam, the same stuff pool noodles are made of. Doesn't have to be packed solid. I stuff pieces between the walls and the gizmo and above the gizmo. I drain my IG only to the mid skimmer point and usually drain as needed during the winter. I have a high water table and don;t want to risk floating the liner.
Al