I find that my AV's grow very flat if too much light. Conversely, too little light and they reach up. In regards to brown spots that depends. Could be from splashed cold water on the leaves while other spots can be from lack of ferts. I'd say you should get a light meter and get an accurate foot candles measurement and then you can rule out the light. I use ferts regularly at half-strength and don't have any issues. Also make sure ur pot is a third of the diameter of the plant. bioWheel

African violets prefer a lot less light.

The owner of a commercial orchid farm, Hauserman's Orchids, used to throw African Violet leaves onto the ground under his benches. The light was so dim under these benches that no weeds would grow there. There the African Violet leaves would sprout, take root, and grow to over 2 ft. wide.

I just visited a local private greenhouse owner who collects violets, tons of them in FULL bloom..
My GOD they were so beautiful...I remember seeing his regular flurescent bulbs at least 1 foot up over them...
He also said he feeds them at every watering at 1/4 dose than recommended..Now if I had thought to ask him what he feeds with and how long he keeps his lights on, I would of been good...... Sheesh...