I was just thinking as I looked at your pics that it seems that its a pretty big plant you have there in a relatively small pot. It has that look of tight narrow leaves. You said you up-potted to a slightly bigger pot about a month ago - perhaps a transplant to a good sized pot and some quality fresh soil?
It does help you to check every so often what your out going PH is too. If you've been flushing then the buffering in your soil maybe getting depleted - also you probably already know by now to let her soil dry out good before watering again.
I'm sure she'll love the new light your getting for her too.