how long do MH bulbs last?

[lewismw]

I am wondering if MH bulbs slowly lose their light output or if they just stop coming on when they go bad. In either case what is the average life spam of a 400W MH bulb running 12 hours a day?

[lewismw]

..

[ONEMANBAND]

6-10 months works for most as time to change the bulbs, bulbs will still light up , color spectrum shifts as bulbs age

[lewismw]

thank you

[jda]

I use mine for a year at 9-10 hours per day.

[gath2]

It really depends on how long you have them on per day. Some people run them only 6 hrs vs 10 hrs. 10 hrs a day for one year is probably pushing it, but then I'm sure it depends on the bulb also. 1 year is a good time to change the bulbs. You may also notice an algae bloom when the bulbs get older and the spectrum changes. It would be good to take note and change the bulbs earlier next time :)

[Gooli]

thanks