Unexplained fish deaths

[H2okie]

In the past 2 months I have lost every fish in my tank and those that were introduced. Per my local fish store, I put in a polyfilter to remove all potential toxins. I kept it in my trickle filer for 3 weeks. I also had my fish store test my H2O, and everything was in the acceptable perameters. They also suggested I check for voltage (as none of my fish made it 24 hrs) but no voltage was detected. Yesterday I introduced 2 yellow damsels. Today they are both dead.

I do have some corals (mushrooms and colony pollups), hermit crabs, and a sand sifter star fish which are all doing fine.

Does anyone have any suggestions? I'll be happy to provide addional information. Thanks, in advance, for the help.

[FishDaddy]

H2okie,
Welcome to The Reef Tank!
Sorry about your losses. The causes of such deaths could be many so I would ask for some more detail about your aquarium.
Please give us a detailed description of your tank and setup, such as rock, substrate, filtration, skimmer, powerheads and tank parameters. How long has the tank been setup? What are you using for source water? Are you adding any type additives? What did the LFS test for and what were the specific results? How do you acclimate new fish to the tank?
Damsels are among the hardiest of fish. For two to die under such circumstances does indicate some serious problem but could not begin to guess without more info.
Dick