I just purchased a Hot Springs Grandee tub. I am going to pour a concrete slab under my deck for it, but does anyone know what a good ballpark thickness I should pour?? I live in Maine if that helps.........Do I have to worry about the frost line???? I am soooo confused.

6" of cement with reinforcement (mesh/rebar) and 6"-12" of stone under the slab. Best to check with your local dealer as to what's typically done in Maine. Or your local building official. Here in CT, the above is adequate.