Tank problems

[captexas]

Alright, now I lost my second cleaner shrimp! I'm getting worried here :(

[NaCl_H2O]

What's your SG and Temp? Are you sure your SG & Temp measuring is correct? I have had Temp and SG swings due to faulty testing! I now have dual thermometers, and two methods for cross checking SG now (Refractometer & floating/bulb hydrometer)

I will never trust one source for temp or SG again!

[captexas]

Temp is ok, I have my chiller on a temp controller which has it's own temp probe and I also keep a glass thermometer in the tank. On the SG, I thought of that tonight. I use a refractometer that I calibrated when I got it like 2 years ago so that could be off. I can't seem to find my cheapy plastic hydrometer to get a basic cross check on it so I'm not sure. I know shrimp are more sensitive to SG changes so I need to check it somehow.

[GaryP]

Are you running carbon in your tank? If not, I would suggest it. There could be some sort of toxic organic compound that is undetectable at fault here. If nothing else, it will eliminate one more possibility.