Meridian tile Stove water coils

[badlash]

Im about to build a covered deck and I've always had the dream of building a wood fired hottub. There is a meridian tile stove for sale locally and in their brochure the mention the capability of adding water coils to heat water. I've had trouble finding any addition information on that process. is that something you can find or would they have to be custom made? Any experience or wisdom would be greatly appreciated. I like the idea of having a dual purpose stove for heating/ambiance in a seating area but also could heat a hot tub.

Thanks