How often to replace bulbs?

[Todd2]

Hi all,

Growth in my 20g tank has seemed to slow down in the past couple of weeks. I have around 2w over the tank. The bulbs have been in there for about 10 months. I think I read somwhere that bulbs lose their intesity after 6 months. Is this correct? Could this be the reason for why my plants are growing so slowly?

 

[malkore]

NO or PC lighting?

NO's should be replaced about 9 months.
PC's can be used until they stop working.

 

[Todd2]

I have NO lighting. So I guess they need to be replaced.

 

[malkore]

Yep, but keep the old bulbs for use in non-planted tanks, or for a shoplight if you have a garage.