How often to change MH bulbs?

How do you know when its time to change them. I leave them on about ten hours a day.

 

It is my understanding that if you have them on for 10-12 hours a day you should change them once a year.
Halides in general lose about 50 percent of their output after a year to a year and a half of burn time. So do fluorescents.

Jim

 

Diver is right, around a year is a common rule of thumb with halides.
Fluorescents burn faster though - significant loss after 6 months from what I read.

 

I've read the Aqualine 10,000 loses less than 25% in a year? Dont know how many hours of burn in though...

 

the cooler, bluer lights ie. 20,000k lose intensity faster than say 10,000k. General rule is 1 year though for replacement.

 

I guess I will just buy one and see if there is a big difference and go from there. Thats cool then I was hoping it wasn't as frequent as Flourecent bulbs. The two I have are about seven months old now.

 

Any one ever use the new XM bulbs 59 bucks 175W?

 

Friend of mine is using the xm 250 halide bulbs and loves them.

 

I bought a xm 10k 175w bulb to replace a coralife. way to yellow. took it back for a coralview.

 

10-12 months depending upon useage and coral reactions/behavior.