There are a few shrimp diseases out there, and I am wondering if perhaps you have accidently bought a disease in with the shrimp? On the dead shrimp are their bodies all perfect? Do they have any signs of what looks like fungus on their bodies? There is even a deadly shrimp disease that looks very similar to the berried eggs on a female shrimp. There are other diseases that are harder to spot that cause a rust like colouration on the shrimp and also pitting on the shell.
In my experience the only times I have had cherry shrimp mass die has been when a heater malfunctioned and cooked the poor thinks (yes a red cherry shrimp cooked is still red), or when a filter has stopped working and I haven't noticed quickly enough.
I hope you can sort out the issues going on with your shrimp because they can be very rewarding and interesting critters.
This link might help if you suspect a disease in the tank.
http/shrimpkeepersforum.com/forum/topic/5052-shrimp-diseases-and-diagnosis/
In my experience the only times I have had cherry shrimp mass die has been when a heater malfunctioned and cooked the poor thinks (yes a red cherry shrimp cooked is still red), or when a filter has stopped working and I haven't noticed quickly enough.
I hope you can sort out the issues going on with your shrimp because they can be very rewarding and interesting critters.
This link might help if you suspect a disease in the tank.
http/shrimpkeepersforum.com/forum/topic/5052-shrimp-diseases-and-diagnosis/