Quote Originally Posted by bstreep View Post
Dr. Mark, one thing no one has mentioned:

The reason I keep my xenia in my 55 well trimmed, is that they absorb toxins. That's cool, but when they die, they can crash the whole tank, as they then re-release those toxins.

In your shoes, I'd continue doing large water changes - like you are doing. I'd also run a bunch of carbon.
Oh, and I did run carbon on that tank and had replaced it about 6 weeks ago.
mark