What was the decor? If you 3 tanks up and running, then we all know It's not the water. That narrows it down to just that tank.D12DetroitD12;4835847; said:I did add 2 pieces of decor that i got from my lfs and i thought that may have been the problem. i have 3 other tanks set up and haven't lost a fish in any of those yet and they use the same tap water for wc's.
Doing a 100% will dilute the problem that killed your fish (if that's the case). Fill the tank, wait a day or so, test water after the day is up, If all checks out good, put the fish back in. IMO. As for prime, add the recommended doses for your tank.