The tank has not been treated for copper, and honestly, I had no idea that was a thing. I will definitely look into this if I ever try again. The tank water I used from my bigger aquarium has an 8 ph and the ammonia levels are in the "safe" range. Less than .5. I have test strips that I could use to provide the other details, if it would be helpful.
There's no "safe range" for ammonia. You want it at 0 or extremely close to it. There are better test kits out there. Test strips are not the best. Anyway, read up and read up some more if you'd like to try at it again. Part of the fun is in the research!
And sorry to hear about your crabs btw.