1. How do I determine the correct size pressure tank for a pump? 2. What are the pros/cons for using galvanized or sch 40 or sch 80 for plumbing inlet/outlet on the pump? 3. Pros/cons for 120 or 220 volt electrical supply? 4. What is a "packer"? I frequently hear this term when reading about deep well pumps. I am trying to learn more about pumps and where the water comes from. General knowledge........ better understanding as a whole.