Hi Paintedpony.
Your well guy may be recommending a 20 gpm pump because that is all your aquifer can sustain. Pumps, wells, and groundwater aquifers can be a complex subject.......to simplify things for this discussion, you will only be able to use a 50 gpm pump if your well can produce enough water to keep up with that demand.
If in your area, your aquifer can produce a large quantity of water, and you can run a 50 gpm pump...awesome for you......and Good luck.
