We received a hot tub and are trying to build a deck for it. It is a large tub that sits on a surface. (Not a built in). We are building a 10X10 deck. How many concrete supports do we need to use to support the tub. I have no idea how heavy the tub is. I would venture to say it is a 4 person tub. It measures 6 1/2 X 6 1/2. Can you help us out?