Helo, Brine shrimp napauli are raised in a salt water..so, The conductivity of Your water incraeased by the solved salt… I wrote some of my expierience with this subject in some old topic… Conductivity of water in my young paros tank increased from 50 us up to ~500 us ! – but water hardnes still stay in the same level.. my young paros were doing well and there was no problems with them. Regullary water changes will solve problem of salt concetration..:)
Greetings!
Marcin Chyla
http://www.ekologicznerozwiazania.pl