Fluorescent lights are great, long-lasting and economical, but sooner or later they'll need replacing. Before they do, they might start acting up -- so, from deep within the Carey Brothers vault of bright ideas, we bring you tips on trouble-shooting fluorescence. If the bulb blinks on and off, it's the obvious time for replacement. If tubes hesitate or are slow to start, the starter (if you've got one) or the ballast needs replacing. If the light "swirls" down the tube or flickers, it's because the tube is either new or cold. Just leave it on for a few minutes and it should disappear. An orange glow at the ends indicates you need a new starter. Black at the tube ends means the end is near. A loud humming is also common. Vibrating fixture parts cause this humming. Tighten all screws. If that doesn't clear it up it's time to replace the ballast. And that's the On The House tip for today.