Here is one tip for the month-
If you ever encounter dying shrimp colonies, meaning one or two shrimp die off one by one each day, its good to catch the remaining ones, adjust them well to another tank. Parameters need not be the same for the new tank.
The another tank that housed these remaining shrimp has to be a stable old tank.
Meanwhile please sterilize the problematic tank. How to sterilize ill post some steps in the future.
Cheers.