Newbie in Minnesota

We just purchased a used 26' above ground pool which we put half in the ground (on a hill). I could share with you a million mistakes we made, but the long and short of it is that we love our home, loved our natural pond and island, but we couldn't handle swimming in the pond after mid July because of cercarial dermatitis. I do a ton of gardening (vegetable and flower) and need to unwind and loosen sore muscles when I'm done. After installation and before we've created decking, I now have a home that is a vacation home we can enjoy almost year round.

I'm looking for information more from the northern, noncoastal 25% of the US. First, do you feel it's better to remove the liner every year or leave it half filled with water and let it overwinter in the ground? Second, do you have any advice you could offer me as far as chemical stabilization? We used well water (38 hours to fill it), discovered we had a high PH and alkalinity in our water and over time dumped a full gallon of muriatic acid in it (still slightly high), discovered the water turns a slight green tint after every pool shock but use a metal sequestering agent to remove it satisfactorily after just an hour, and I test it daily, if not more often. I seem to have stabilized many chemicals but still discover my chlorine levels are low. I have just read I need to add liquid chlorine daily. Where is the best place to buy liquid chlorine?

Hubby argues about putting the cover on it as he's afraid wildlife will look at it and think it's solid...thereby falling in and destroying the pool when they're trying to get out (we haven't built a fence yet.) Are covers yay or nay?

Last, if you've had your pool for several years or better, do you have any wisdom you could impart to make it last, make it more enjoyable, and make it everything I've wanted it to be?