Bulb replacment

[Johnny Quest]

I've had my reef tank up and running for about 8 months now and am wondering when I should replace the existing bulbs.

I have a 120 gallon tank (60" x 18.5" x 25") using 3ea 140w 60" VHO Actinic fluorescent and 2ea 250w 10,000k double ended metal halides. I'm currently running the fluorescent lighting for 10 hours a day and the Halides for 6. I've heard 6 months to a year for the halides and 6 months for the actinic VHOs. Am I overdue?

And.. When I do replace the bulbs, are there a certain procedures I should use in order not to shock the inhabitance in my tank?

[koj11]

I replace my bulbs yearly.

[griss]

I replace MH bulbs yearly. I replace VHO's every 6-8 months if they are run on a magnetic ballast and every 12-18 months if run on an electronic ballast.

[jgoodrich71]

I agree with griss, just do not replace all of the bulbs at the same time. I run 4 VHO and one halide. I replace only 2 VHOs at a time. Usually a month ot two apart.