Why is LFS doing hypo salinity and copper and what level of copper is in the stores water As a former owner of 2 LFS in Brklyn NY and someone who has acclimated thousands of fish I would say honestly it could be the collection of the shipper or the LFS is not telling u something else they are using these fish should never die after 2-3 weeks and thats usally a sighn of poisoning as in cyanid collecting or LFS using to much copper or a diffrent chemical they are not telling u about i would not do copper and hypo togther in my shop i would have a seperate quarantine system in back with a big uv and treat with copper only when needed and sold and acclimated thousands of fish never with any major problems try a diffrent shop Best of luck