Its a new set up and the rock was just shipped in?? your going to have die off on the rock its normal. Seeing the tank is new your calcium should be ok for now with fresh saltwater in the tank.
Let the tank cycle first and then worry about prober calcium and alkalinity levels. IMO
you dont want to be using additives while the tank is in cycle.
Read up on coraline algae on the site, there are tons of post on this subject....
Sit back and don't worry while the tank cycles only keep track of that for now, that will be enough..
test kits needed to start...
ammonia,nitrite, nitrate, calcium, alkalinity and PH
. If you start seeing algae issues the phosphates would be a good one to pick up.