Well a new tank, like you have, is no place for shrimp to live. They are very sensitive to Ammonia and Nitrites and even nitrates (in elevated levels). And just assuming that pH swings are not harmful to shrimp because you have read that they are not harmful to fish is also dangerous. Shrimp are much more sensitive to this sort of thing. Knowing your pH in your tank, as well as your tap is important.
And no, not all homes have copper pipes. I do not! And for the most part homes with copper pipes can still have shrimp safe and happy. The copper its self will not leach (after a few months) unless the pH of the water is very low. So if you are not in a new home, or you have a normal pH in your tap water, it shouldn't be a problem, but if you do live in a new home or have a low ph out of the tap, it could be a cause.
Basically, after what you have explained, your shrimp have MANY obstacles against their survival. Your tank is 2 weeks old, that is no where near old enough for shrimp with an inexperienced shrimp keeper, and many experienced hobbyist as well. Your shrimp are new, so they are stressed from shipping and then are thrown into water that is less than optimal. You have a cheap test kit so you can not be sure what your ammonia and nitrite readings are. You say you have had the tank for 2 weeks, and have experienced losses of shrimp after every water change which leads me to think the shrimp have been in there since week 1 at least. And where exposed to high levels of ammonia.
My suggestion is to allow the tank to cycle for at least a month. After that try again. Your water conditioner is not the problem. If this post sounds harsh, I am sorry it is not meant to, there are just many problems that any one of them could kill shrimp!