Cecil, you have an open system. You say it's 20 gpm, but have you verified it?
How big is the well for your house, and do you run two different wells? One for house water supply and one for geo water supply?
Flow out of the discharge is probably not 20 gpm but the pump for the house had to be 20 gpm to run the geothermal. I haven't actually measured it but if I remember I will do so when I drain the pond.
One 4 inch well 20 gpm for the house and geothermal.
