Cannot keep Xenia

[Voxboy]

Everything in my tank is thriving. I originally had a 55 gallon and had to upgrade to a 120 because my softies were growing out of the tank. A few years back I had a 90 and tried to grow Xenia but it never took. I got out of the hobby for a couple of years....so when I set up my 55g I remembered the trouble I had trying to keep Xenia alive.....all my other friends at that time had to literally take bags of it out of their tanks. Fast forward to 3 weeks ago. I was in the LFS and there was this one pound rock full of Xenia....I thought what the hell, I'll go for it. 3 Days after being in my tank they withered away. They didn't "melt" but they are closed so tight I can hardly see them. Everything else is doing great. All parameters are 0 except Nitrate which is between 5-10ppm. No issues with tank inhabitants bothering them. I have moved them twice Less light, more light, less flow, more flow ect....
I do run quite a bit of carbon however and have heard that Xenia do not like carbon....any thoughts?