any measurable nitrite is a problem. Kenya trees will go through periods of retraction where they get sort of stiff and lose some color and drop some branches. It's one way that they reproduce. The dropped branches can attach and grow a new colony. As long as a small piece of the original colony remains it will grow new branches and form a colony again. If it's been retracted and melting away for a month though, you have a problem within your parameters somewhere. They can be damaged by more aggressive corals as well. What was it next to before you moved it?