Metal halide bulb life

I have heard recommended bulb change intervals between 6-12 months are common but had planned to replace mine 9-12 months. Lately I have been noticing a large amount of algae growth and decided to just change the bulb and see what happens (bulb is 6 mo old). Old bulb and new bulb are both coralife 150w 14,000k. The difference was immediately noticeable. Old bulb = yellow, new bulb = blue. I am shocked that with only 6 months of use the bulb had deteriorated so much. Hopefully this solves some algae issues.

 

Thats weird. I changed out my 12 month old 175w 14k e-bay halides, old one had lost its blue tinge to it and slightly diminished light output.

 

I found it amazing that after only 6 months that it had lost a huge amount of its blue spectrum.

 

What type of ballast is driving it?

 

good question, I don't have it in front of me nor can I find details about it on their website. its for a biocube hqi so maybe oceanic or coralife