Sounds like the major change recently because the fish was the filter floss. Remove that and see what happens. Also keep an eye on if any of the fish are nipping. There's very little for them to forage and tangs need tons of grazing.
When the foxface died, how long was it rotting? Still it's very strange to have a fish die within a day unless something happened to it. How did you introduce it again?
Almost instantly got the fish it out. It wasn't sitting in there to decompose. My filter floss was gunked up alot when i changed it. The Issues came after I swaped it with hammers to a clean floss. The very next morning issue started. They were looking great before that.
I wouldn't call it scientific by any means butnmy general thoughts if it makes since? Is the dirty filter floss probably was the last remaining Po4 source. Took that out and not much left. Skimmer isn’t producing skimmate either it did last week. This week not a drop.
My filtration on my main tank isn't this efficent so i have to use Rowaphos. All water in this tank has to go through the filter floss and skimmer section. My main tank some of the water slips pass the filtration.
The tank was Heavily seeded from rock and biobmedia from my main tank. If that makes a difference.
I also only feed once a day same as my other tanks.
I could turn skimmer off as someone recommended but as mentioned earlier it hasn't been skiming anything this week so not really sure it would make a difference?
I have tons of food pellets/flakes/ phyto I could feed the tank with, if thats recommended? i started with reef roids thinking not to start by doing anything extreme.
All that stuff i rarely ever feed in my main tank do to higher po4 issues.