lightbulb lifespan and issues?

[ccLansman]

Just wanted to check, i have had a set of CF bulbs for over a year now and they are starting to turn brown on the plastic part and the light is a lot duller then it used to be. As the bulbs get older do they become less effective? Is it bad to have old CF bulbs? I don't really have an algae problem anymore but have heard that old bulbs can lead to increased algae growth, any truth to this?

 

[tedr108]

I have read in several places that yearly replacement of bulbs is recommended. A bulb's effectiveness decreases before the bulb burns out completely, so I wouldn't wait for that.

If the decreased bulb effectiveness hampered plant growth, I guess it's possible that algae could benefit from that.

 

[Mooner]

I've seen PC's diminish as early as six months (PAR readings)(anyone else tracking their lighting?). I've also ran them for a year and up to complete burn out. IME the tanks adjust to the lower light levels/slower growth. One things for sure, when you replace these old bulbs the system will go through a shock (ie more intense light/new bulbs)

 

[Gerryd]

Hi,

No matter what type of lighting I used, I replaced my bulbs between 6-12 months old at most.

When I used normal flouros, every 6 months.

That way there is not as much variation in the growth due to the diminished light.

I would definitely replace them and expect to increase c02/nutrients in response to the increased light.