I'd like to get some post-installation feedback on my standing column system. Some background: I live in New England where standing column designs are fairly common. In New Hampshire domestic wells can be used for dual purpose exchange/potable water. I have a 395 foot deep well with the static water table at 100 feet. With most designs I am aware of, pumping energy is relatively high, especially when the pump serves double duty for house pressure. In order to reduce pumping energy I figured I needed to reduce the head - which I did by taking the unorthodox approach of working with the natural suction created in the return line. By installing a second pressure transducer on the VFD with a different range, the geo system operates at 20" mercury. When the house usage exceeds what is stored in the pressure tank, the system switches to house pressure to refill the tank, then switches back to low pressure operation. At the end of the cycle, the system pressurizes again to reduce mineral precipitation in the HX. The upshot is, I'm pumping 7 gallons per minute through a 3 ton unit from 100 feet underground using only 1.5 amps. My installation cost was a fraction of what new bore holes would cost me and the house usage effectively serves as the bleed on the well. All the concerns about air infiltrating the system have yet to materialize. What tiny amount of air does get in there is not in contact with the water for more than a minute or so before bubbling back up to the well surface. In another unorthodox move, all domestic water is routed through the unit's HX so the water is never stagnant - it is always fresh water drawn from the bottom of the well. There's more to it than just this, like trying to correctly size a pump for this application, but this gives a pretty good idea of what I did. I should also note that the pros I worked with fought this design tooth and nail (as they should) but in the end had to admit that it was a novel solution that may or may not work for others. So, "others", what do you think?