I was running a reef tank w/ fish with no issues when a Rasta Leather suddenly died off (turned black overnight and was entirely gone in hours), that led to my water going south quickly causing a number of other corals to die off in the process until almost all were gone. All of the fish and inverts survived, the only two corals that survived were a Staghorn and a Acro.
It took about a month to finally get back to normal water levels and they have been steady for over a month since then so I started to restock the tank with LPS and inverts but everything new that I have added in has died quickly or in the case of inverts almost instantly (the current tank inhabitants have had no issues whatsoever fish coral etc).
The LPS I added all died from brown jelly disease, since the water was stable I suspected something in the tank may have been nipping at them so I gave it another month and then bought a few small frags and put them in the refugium to eliminate the possibility of nipping. Same result all got brown jelly disease and melted to nothing.
In addition to the corals dying, the shrimp I added into the tank along with the urchins all died either instantly or within a few hours. I drip acclimated both from 2-3 hours before putting them into the DT.
I don't really dose much into the tank other than calcium and phyto/zooplankton. I was dosing NoPoX to get the water back to stable then stopped and let the chaeto and mangroves handle the task instead which they have done efficiently. I also had the LFS test the water for copper since that might explain the inverts dying and that came back negative too (0).
I do water changes of 10-15G a week on average when the tank is running normally. I also changed about 50% + of the water immediately when I had the Rasta Leather die and followed that up with 25% changes weekly until the water stabilized. I have tried adding corals and inverts into the refugium to make sure nothing was stressing or eating them in the DT and had no luck with that either.
I am struggling to understand what could possibly affect new tank adds only, as mentioned haven't lost a single fish over this entire debacle, the inverts that were in there are all still healthy, and the two corals left which are arguably the most susceptible to health issues from water quality are both fine and thriving.
Anyone out there ever experience something like this where livestock being added to the tank dies quickly or instantly? I have troubleshooted pretty much everything I can think of at this point and am just wondering what else I may have missed? As you can imagine this is quite frustrating as I only started into the hobby to have a tank of LPS swaying in the current and ended up with a LPS graveyard.
I would suggest that you get a small quarantine tank started. Like a 10 or a 20 gallon and have it cycle like any other new tank before putting corals. Quarantine your corals for approximately 4 weeks monitoring them closely. And also do your research and start off with the hardiest lps corals you can find and add them 1 by 1. This will give you less room for error. Also dip your corals to make sure to rid of infections and parasites.