My open loop water to water geothermal unit seems to be struggling to get up to the thermostat heat temperature setting. I measured the inlet and outlet water temperatures and it is less than a half degree difference. I previously had it dialed in nicely but apparently that has changed. So as I understand it I need to slow down the water discharge to allow longer time for the unit to extract heat from the inlet water, but my question is simultaneously do I need to also increase the amount of water flow into the unit from my well? The Bosch Geo unit is only 4 years old and my water quality always test good.