MH Bulb lifespan

[beattyr]

Im curious as to the useful life of a 6500 Ik 250W bulb? I have one thats about a year old now on my tank. Should I be replacing it now?
Also, do the power compact Actinic bulbs need to be changed regularly as well due to freq shift?
Thanks
Rob

 

[jacksonpt]

I read a "study" done by several people on another SWF board... they came to the conclusion that the amount of useful light put out by 2-year-old 6500k Ik bulbs was not significantly different that the light put out by a brand new bulb.

 

[bang guy]

I agree with the above statement.
and.... Actinic bulbs are monochrome and therefore don't experience a frequency shift. However, the phosphors in the PC Actinics degrade at a good rate so the bulb outputs significantly less light after 6 months and a mere fraction of it's rated light after a year.
This does not apply to the 7100K blue PC bulb, only on the Actinics.