I think old beans might be problematic too, but in my case, I have bought new beans at least 6 times, and at first I thought it might have been old beans, so I bought them at different places. What are the odds that in 6 times at at least 5 different stores ( in two states) that I got old beans?
And the fact that I've never had a problem before cooking beans in WA, KS, or Germany, or at the two other houses I lived at in Mi where I had city water.
And now the beans I cooked today are perfect...they were made with reverse osmosis water.
I say, if your beans are not getting soft after hours of cooking ( 10) and/or if they are shedding thier shells that have the texture of pill capsules, then it's either old beans or it's your water.
I found this link which mentions dry beans and hard water.