Soil remains damp. I'd eliminated those possibilities. Leach extra salts out by dripping water through soil for 30 minutes, allowing all excess water to drain. Not blooming, stalks growing almost straight up. I get very little light in my apartment, if you get more, a lower wattage would probably be better.
Plant forms a stem with no leaves.
This is just a symptom of age. As the older leaves die, a space develops between the lower leaf level and the soil. This isn't a huge problem, per say, but it's not attractive. To relevel the plant, remove it from the pot, cut off the bottom of the root system enough to put the plant back in the pot and add dirt to the top to rebury the stem.