# When to change CF bulbs



## Jack W (Apr 8, 2005)

I have two 36w CF lights over my 20 gallon tank. I can't remember how long ago I bought the bulbs. My question is how long do CF bulbs typically last at 12 per day operation and how do you tell when it is time to replace them. Do they burn out, and how effective are they just before they burn out.

Jack


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## trenac (Jul 16, 2004)

I've had PC bulbs in now for 3 years and they are still going strong. I've been told to run them until they burn out. As soon as you see the light diming then replace them.


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