I'm not sure why the leaves are turning brown like that... did any of the roots get torn or something?
The new growth looks more promising though.
Also, is it possible to move the lights any closer or are they already close? When growing under T-8s or T-12s, the more the better, especially when under the humidity cover, since it blocks a certain percentage of the light. I had mine about 2-3 inches above mine when I got it (before I took it out of the cube) and the leaves started to develop red tentacles within 2-3 weeks. Also, the extra warmth helps too.