can't keep fire shrimp alive

[shan820]

Can anyone help me figure out this fire shrimp death trap I have created???

Last week I bought a fire shrimp, acclimated as I always do, and added him to the tank. Looked good that night. Day two... missing. Day three... found an empty shell. Figured he was dead and someone ate him. Day four... a miracle he re-appeared. Apparently the empty shell was just a molt. Day five... dead again. But completely unscathed, no bites.

This week, made a second attempt. The exact same thing happened! After having him for just two days he molted and died! We also added two halloween hermit crabs, 2 pep shrimp, and 5 snails the same day we added fire shrimp #2. As far as I know those guys are still alive.

Quick summary on the setup. About a month ago upgraded from a 40 gallon to a 75 gallon. All inhabitants survived the move with no trouble. This includes: 1-6 line wrasse, spiny urchin, pistol shrimp, purple lobster, snails, ~30 lbs live rock (including several soft corals and anemones). The majority of the water in the tank is 'new' since we had to buy more than 30 gallons of RODI from the LFS. But after three weeks with all the LR it should have been pretty good.

Todays params:
Temp: 76
SG: 1.024
pH: 8.0
Ammonia: 0
Phosphate: 0

What am I doing wrong? Been in the hobby for years, thought I knew what I was doin. I feel really bad. Not only have I wasted alot of cash but I have lost two beautiful shrimp. I really want to add a couple fish now that I have the big setup, but I am afraid to.