MH question


New member
I ran my old bulbs for almost a year before i visually noticed a difference in algae and coral growth. So i would say around 10 months or so. But i also tend to use my bulbs life and plus some.


New member
Depends on the brand.

I change out my DE 250 watt bulbs about once a year.

I know a hobbyist who changes his every 1.5 years.


New member
+1 on the 10 months. I start to see algea growing on the sand and the corals start to complain. It's time to change bulbs.