I am interested in installing a Grundfos UP15-10SU7P/TLC recirculating pump on a dual water heater setup. The tanks are presently installed in parallel with the two outlet lines rising overhead to tie in to the horizontal line. I am unsure where the Grundfos pump should be installed on this particular setup. Should I change the setup so that both tanks merge into one vertical rising pipe and install the pump on that single pipe or should I install the pump "downstream" from both tanks to circulate the water away from the tanks toward the far end of the house to the bathrooms where the transfer/comfort valve is located?