The heat pump needs flow but only about 20 PSI pressure. The house needs 50 PSI pressure but not much flow. When running the geo if the pressure is 30 PSI steady, your pump is marginal size. Putting in a larger pump will give you better pressure at the house, but can cause your pump to cycle on/off repeatedly while running the geo. Sounds like your pump was size perfectly for the geo to keep the cycling from happening, which means it doesn't really supply enough water for both the geo and house. Adding a Cycle Stop Valve to the larger pump will make it supply exactly what the geo needs without cycling, and will increase flow and deliver strong 50 PSI to the house when needed also without cycling. Don't want much larger pump than needed for efficiency purposes, and picking a pump that will drop in amps when the flow is reduced is also important. Give the specs on the flow needed for the heat pump, well depth, water level, existing pump size, and we can help with the right set up. With strong constant pressure from a CSV the heat pump will not cycle the pump to death and you won't even need soap in the shower.