Halide bulb longevity?

[christhereefer]

I have used a 250w double ended metal halide bulb for my reef tank for a few years now. I have used the 10k, 14k, and 20k of various brands. It seems that some of the bulbs I've used, have lasted 8 months while some need repalced after 5. I usually just buy the cheapest bulb I can find and to be honest, I've not paid much attention to which bulb is which. Have any of you noticed a brand which lasts longer than others? Also, does the Kelvin rating have anything to do with the bulbs longevity?

 

[aquaguy24]

Temp and keeping bulbs cool helpsthem last longer also the ballast. Electonic ballast are more effecient which make the bulb last long. Sorry can't answer about the kelven rating. Maybe someone who has more experience will chime in.

 

[hurt]

There is a difference in the life span of bulbs as far as Kelvin is concerned. Most 20K bulbs last only 6 months before their spectrum shifts dramatically. While an Iwaki 6500K can last 2 years before the output falls substantially.
Of course if you overdrive your MH bulbs with HQI ballasts, that will also shorten lifespan of the bulb.