fluorescent bulb replacement

[matilda'skid]

I have fluorescent bulbs of all ages. I am not using any that are starting to get black on the ends. How often should the bulbs be replaced. Should I be marking them somehow and discarding them at a certain age. I am assuming they get less efficient. I am not worried about the energy cost but adequate light to the plants.

[Doug9345]

They typically maintain 85% of their initial output over most of the life of the tube.

[RJGlew]

Originally Posted by matilda'skid

... How often should the bulbs be replaced. Should I be marking them somehow and discarding them at a certain age...

An easy to understand page:

http://www.waynesthisandthat.com/fluorescent.html

[matilda'skid]

Thanks Doug and RJ Very interesting link. The guy who did the experiment was very organized and followed through on his quest. I am interested in light but haven't taken the time and effort to study it. I have diffraction grating things in my windows that make rainbows and too many stained glass pretties in my windows. I loved a kids science museum where red and green made yellow, but why am I too lazy to find out more. The GE kitchen and bath did well and would be reasonably priced I think. I don't see f bulbs ever marked down at my Wal-Mart.