power compact bulbs time to change?
 

how long do pc bulbs last?
ive got a corallife combo mh/pc/moonlight setup thats a year old.
thinging of doing a bulb change but not sure if it necessary.

do old bulbs increase hair algae growth?

PC's shouldn't be run more than 6-9 months. That would apply to the 10k's, but I'm not sure about the actinics. When old bulbs shift the spectrum of light they put out, it can increase nusciance algae.