You said the water is cloudy, was the salt completely dissolved before you added it to the tank? Did you accidentally disturb your livesand bed when syphoning/pumping out water? Syphoning/pumping water in? Was a filter running dry for a period of time so that some bacteria dies off causing an ammonia spike? I'm not positive but I think a spike of .5 isn't going to hurt too much, its not good but not totally fatal either. Shrimp are VERY VERY sensitive to quick temperature and salinity changes and thats what I think did your shrimp in. The ammonia issue I bet is one of the above things. Remember, calcium has to do primarily with corals, not fish/shrimp so if you were thinking that had something to do with the shrimp issue it didn't... I didn't read your calcium thread but a 50-60% water change means nothing unless your sure your new water's calcium is in a good range. Many salts out there are sub par in this aspect. I use Oceanic which keeps me at about the 450ppm mark.... However, if you knew this already, disregard lol.
**I say wait it out, let your filters clear your cloudiness and test salinity, temp etc... once all has settled. The worst thing you could do now is to start making changes to your water without knowing EXACTLY what is wrong, you can end up compounding the problem. Hope this helps, keep us posted.
-Josh P
