Shrimp hell- why?

I cannot keep ANY shrimp alive for over three days!




All my parameters (Nitrate, ammonia, nitrite, phosphate, calcium, salinity, temperature) are great and all my corals are fine! :doh:



I have tried (two months apart) a coral banded shrimp, Fire Shrimp, and two peppermint shrimp, only to have them die within days!:bawling::bawling:



I definitely do not want to get another until I have an idea as to what I am dealing with- suggestions? :confused::confused::confused::confused:



(Nanocube 29)