Thanks much to the folks who have responded to this thread!

A local pool store is where I have obtained the results I posted in my initial message; I believe they use a computerized tester. My wife stopped by the store today to get the water tested and gave me the results over the phone; I'm home now and everything I posted above matches the printout.

On my way home from work, I picked up six 96oz jugs of 6% bleach. I brushed the pool when I got home, changed out the cartridges, lowered the water level a couple of inches and refilled with tap water from our well. I then poured all of the bleach into the pool; I will get more bleach in the pool starting tomorrow. (Hopefully it is okay to not add all of the bleach at once.)

I will get the pool water re-tested tomorrow morning on my way to work and will post a follow-up message here ASAP. I will also get a sample of the well-water tested. My wife will stop by our local Walmart and get the recommended testing kit... I'm not chemically savvy, so hopefully it's simple to use!

I have added my pool info into the pool chart as per Waterbear's request. (I was way off on the HP of our pump in my initial post! )

Thanks again for the quick replies; you have given me some hope that my "swamp" might actually become useable again!