These Lamp Troubleshooting Tips were provided by Ultraviolet Resources International (URI) manufactures of aquarium and reef lighting.
Lamps may be leaking in air due to tiny cracks in ends of lamp glass caused by shipping abuse. Replace lamps.
Sockets may be dirty or worn out. Check, clean or replace, if needed.
Lamps may not be properly seated in the sockets. Check that pins or lamp ends are properly seated in sockets.
Ballast may have reached end of life, or may be defective. Change ballast where needed. Lamps will turn black at ends if the ballast is bad.
Standard wattage lamps should use a rapid start ballast, flickering or no light is the result.
Flickering or blinking-usually - caused by defective starters. Replace starter.
Only the lamp ends are glowing - caused by defective starters. Replace starter.
Dark ends - lamps not seated, or defective sockets. Ballast could be defective.
Orange and brown streaks - air leaks due to end cracks caused in shipping. Replace defective lamps.
Swirling - caused by minute impurities within the lamp, which can be eliminated by cycling the lamps on and off a few times.
Thin phosphor, holes in phosphor - these are rare, cosmetic defects, and have no effect on a lamp's intensity.
Every month take your lamps out and clean them with a mild glass cleaner to remove any salt or dust that collects on the lamps due to heat.
Each lamp may react different when it has reached it's life, it may turn a different color or just lose intensity in color or output. Follow the manufacture's recommended schedule.
When installing an internal reflector lamp make sure the writing on the lamp is towards the direction the light is to illuminate.
Check the lamp sockets. Be sure that the lamps are snug in the sockets. Poor lamp contacts can cause difficulty in lamp starting, shorten lamp life, cause premature end blackening, and possible electrical arcing at the lamp ends.