I am looking to install a hot water recirculation system to my domestic hotwater system. I have a Tankless hot water system coupled to my geothermal system with a 40 gallon storage tank. I'd like to install a recirculating system such as a Grundfos Comfort system to have instant hot water available at the taps as well as keeping my storage tank filled with hot water. Can I accomplish this with one pump or would I need one circulator pump with a return loop to heat the storage tank and the Grundfos System to have the hot water available at the taps? Any thoughts?