How often do you change your bulbs?

[Chichas01]

I'm looking to replace my Phoenix 14K bulbs soon and while checking out prices online I came across this really cool article on light output over time for this bulb:
Light Output of the Phoenix 14,000K DE MH Bulb Over Time by Allen Chantelois - Reefkeeping.com

Just thought I'd share.

 

[Brie]

Really good article, thanks for that.

 

[trido]

I read that artical a couple years ago and for a while ran the same ballasts and bulbs. I disagree that bulbs can last that long if you want a rich flourishing tank. I found that my corals would start losing thier rich color and growth would slow after about nine months with his "test setup". I did however run that set up on my frag tank for near 18 months without changing the bulb. The corals did grow, but not as quickly or as colorful on the display corals with newer bulbs.

I could visibly tell my radium 400W 20Ks were fading after six months.

Yes, you can stretch bulb life, but IMO, the general rule of thumb of 6 months for 20K, 9 months for 14K and a year for 10K tend to hold true. Heck, the rule of thumb has been compiled over the years by reefers. Not the manufacturers.