# should T12 light bulbs be replaced?



## fresh (Jul 28, 2010)

Hi all,

Should all T12 bulbs be replaced say once every year or two? My bulbs are old but are running fine; I wanted to know if they should be replaced or not and does it matter for plants?

Do the T12 light bulbs lose something as they get older?

Thanks


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## EDGE (Aug 24, 2010)

Every type of light bulbs do diminish in output over their life span, including LED. 

The general guideline 10+ years ago for T12 was every 6 months. Not sure if this was based off of Salt Water needing intense lighting or base on aquarium hobby as a whole. That being said, I have 2x 30 watt T12 running for 3 years now and the plants are growing. Maybe not as fast as when the bulbs are new, but they do grow. Reflectors do help extend the life indirectly, as more light can get into the tank.


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## Rastapus (Apr 21, 2010)

Light spectrums do shift over time as well as intensity as edge pointed out. As the color spectrum shifts, older bulbs can encourage undesirable algae growth. The general rule is to change them every 9 to 12 months. You wont notice the difference as it is gradual. Usually when the bulb is changed however, you will see the difference.


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## lednail (Apr 22, 2010)

In horticulture we replaced every 3 months. Canadian tire sells the cheepust aquarium and plant T12, about $5 for a 48"


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