Life span of UV light bulb

[mecedesfish]

After using it for 2 years with average of 5 hrs everyday.

How do i know if it is still effective or the life span to change a new bulb.

thanks

[tawauboy]

are there any thing that is wrong with you tank?
this should tell (roughly) you the state of the uv bulb.
if nothing, you may leave it as is. why fix something that isn't broken.
however, you may increase the duration to compensate the drop in intensity.