Replacing flourescent tubes

[LLeopardGGecko]

I've just recently got into using shoplight fixtures for CP lighting, so it's probably been about two months since I bought all the fixtures and the tubes. I've already noticed that some of my cool white tubes have lost some of their brightness. Is this normal?

I remember reading somewhere that it's wise to replace flourescent tubes roughly once every three months since they lose lumens very quickly. How often do you all replace your tubes?

 

[technoracer]

i replace mine roughtly every 6 months. i just write the date i install them on the bulb itself with a sharpie, but this will fade to almost nothing after 6 months.

tech...

 

[chloroplast]

Once per year.

 

[Tamlin Dawnstar]

I used 8 tubes per bank. MArk on the side when installed with a sharpie. My general rule was once 8 months, but they were all in rotation, some newer some older. It depends on what you can afford. The newer the tube, the brighter the spectrum and the happier the plants will be. You can get by with less if you have more tubes, but with 2 tubes and a year running them, things won't be looking too good.