It has been twice in a row now that i have tried to add a shrimp to my tank only to have it die right away. I checked PH 8.2, Nitrite 0ppm, Ammonia, 0-0.25 ppm, and nitrate 0-5ppm. I also tried testing for copper but was not getting a 0ppm reading. I have other fish and hermit crabs in the...