The lamp ·
When to replace a bug zapper bulb (and how to do it in four steps)
A UV tube fades long before it goes dark, which is why so many lanterns hang there glowing and catching almost nothing.
The signs
The tray fills more slowly on warm, still nights. The glow looks paler and whiter. The ends of the tube have darkened. Any one is a hint; two together are an answer.
How long a tube lasts
Around one season of nightly use. Weekend-only lanterns can go two. We swap ours every spring so the lantern starts the season at full pull.
The four-step swap
Unplug and wait five minutes. Twist the tray counter-clockwise and remove it. Loosen the screw on the base and slide the old tube off its 4-pin socket. Seat the new tube, close the base, refit the tray.
Measure before you order
Our tube is 7.75 inches long, 1.77 wide and 0.9 deep with a 4-pin base, made for the Zap T6 Pro, K15, T9 and X3. If your lantern is another model, lay the old tube on a ruler first.
Old tubes
UV tubes contain a small amount of mercury, like other fluorescent lamps. Take spent tubes to a household hazardous waste drop-off or a store that recycles lamps rather than the kitchen bin.
