when to change bulbs

[wetone]

I had another post going about coral growth slowing down and many replys pointed to my lights being old. I have 2 250w 6500K MH's and 2 110W VHO actinics. All are about 12 months old.
The MH's are on 4hrs a day, while the VHO's are on 8 hrs.
Question is how often do you change your bulbs??

 

[k.lee]

Suggested is 1 year for MH
1 yr for pc
6-9 month for other flo's

 

[taku]

Originally posted by wetone:
<strong>The MH's are on 4hrs a day, while the VHO's are on 8 hrs.
</strong><hr></blockquote>
Your MH's are only running at half the estimated daily usage, are they not? So I'd imagine your MH's will be fine for at LEAST another few months.

 

[wetone]

I turn on the halides around 4:00pm and off around 9:00pm. I have them on when home so I can enjoy the corals at their fullest while keeping heat and algae down.
I have zoanthid polyps which are not opening much, they were massive 1 month ago. I dont think lighting is the problem..any thoughts??