African Violet - S. 'melodie'

I couldn't resist passing this plant up when I saw it in Lowe's: It was wonderfully majestic, with frilly white-and-purple flowers. I picked it up for around $9 last May, and it treated me to about a month of blossoms (though I suspect it had already been blooming for quite awhile). It stayed in its majestic condition for the entire summer, and in September -along with my other Africa Violet- it began to grow buds. Though the flowers were gorgeous, for some reason the purple streaks on the petals weren't quite as vibrant as before. I wonder if that could be due to lack of fertilizer, poor MN sunlight, or something of the like? Again, I didn't take pictures of its second glorious bloom. I only have a photo from June or July when it was at the end of its first bloom. Not the most flattering picture, I know, but it's the best I've got. (Love the paint in my old bedroom; thankfully, it's lavender now.)

 Around November, I began to notice that 'melodie' was deteriorating in a serious way. The first two rows of leaves were rotting and turning brown, and some leaves had light green spots. I've inspected it for pests, but I've seen none. I've always been very careful about underwatering and overwatering, and I haven't kept it in a place where the sun could burn the leaves, which is very unlikely in the Minnesota winter. It was in a north window, but I changed it to a shaded south window. I wonder if it could be the cold... Temps here this winter have ranged from the 30's to the -30's, but the north windowsill temps range from about 58-72, depending on the time of day. Temps in the south window range from about 68-78, so I think this may have been the problem. African Violets like normal room temps. However, my other violet was sitting right next to 'melodie' and is doing perfectly fine. My mother and I surmised that 'melodie' might just be old, but I did what I could to save it! Here are some photos of the damage done:

By this point, I had little hope for my once-majestic 'melodie', the African Violet which once gave me gorgeous, frilly white, purple-streaked flowers. The outer 2-3 rows of leaves had begun to turn brown, and I felt the prognosis wasn't very good. The previous day, I had taken two of the healthiest leaves to propagate, so I thought I would experiment... With reassurance, I took a sterilized paring knife and began to cleanly slice off ALL leaves which had brown on them, re-sterilizing between slices. I ended up cutting off over 30 leaves, and I worried slightly whether or not the plant could take the shock.

When I cut off one of the largest leaves, I noticed there was a tiny baby leaf sprouting from its base. I kept this leaf and one more sort-of-healthy leaf to propagate. The rest went in the garbage, much to my distress. I checked up on the original 'melodie' from time to time, and it seemed to be doing great. No signs of infection, which was my main worry, and the "pruning" has stimulated the plant to grow; it has new buds coming up!