I doubt you'll bother to read or respond as you seem the type, but you've proven my point. Using the word "shallow" could have directed us in the right direction.
"standard casing" diameter for me is measured in inches, not feet, and is 200' deep for a "shallow" well and 1100' for a deep well. You're not fitting a second pump in there. Period.
Devil is in the details. Glad you found RPS. They were on my short list if it seemed a good fit, but you were so stingy with info, I couldn't even be sure of that.
Good luck
I'm sorry. What is this comment in reply to? Who referred to "standard casing" as being measured in feet? Who are "us"? Is there more than one of you writing what I presumed to be your individual comment? Or, are you speaking on behalf the entire forum community? Is this in reference to your absolute but entirely incorrect statement, "Well casings have just enough room to accommodate the pump and the discharge pipe. There is nowhere to install a second pump unless you have a completely non-standard well." It certainly appears that you are reaching for an excuse for your mistake and at the same time losing credibility. Perhaps, I am just a little confused as to who and what you are responding to as well as what you're saying. If so, my apologies.