shrimp & invert problem

[fchaulk]

Nope , brand new tank when I sold off all my freshwater. No copper has been added or was ever in this tank. I forgot to mention that a feather duster I have once looked like it died but after a couple weeks it seems to be almost back to it's full size. I (or my wife wince I am in Africa now) have been adding a small capful of ??? , (have to get my wife to email the product name) every couple weeks but the shrimp were dying before I put the feather duster in and started doing this.

Thanks
Frank