Unless I'm using a compact fluorescent bulb, I don't use anything smaller than the 48" bulbs and two or four of them at that. It does sound like the light is the issue to me.
Are you using the same water for all of them? When my plants started to inexplicably fade and die on me it was due to the water machine that I was filling my bottles from having not been properly maintained.
But it does sound light related to me as well.