View Full Version : Does a light's useful energy die?

05-30-2008, 02:27 PM
I was reading somewhere about reef lights, and I heard that most fluorescent lights stop giving off the needed energy after 6-8 months. Is this true? Do I have to change the bulb(s) every 6-8 months?

05-30-2008, 02:45 PM
thats a good question. I know that regular fluorescent lighting as well as the full spectrum lighting I use for my parrots quits being 100% when the ends start to turn black.

05-30-2008, 03:28 PM
I think it depends on the type of bulb. The Power Compacts should be replaced every 6 months. I think the T5's can go for about a year before they need to be replaced (one of the big benefits of T5's). There are also variables like excess temperature, that can shorten bulb life.

05-30-2008, 10:57 PM
So how do I know if I need to replace a bulb? Can corals die if I don't replace it?

05-30-2008, 11:03 PM
T5 Bulbs actually only lose 5% of their intensity over the life of the bulb. It's not so much that they lose their usefulness but rather a change in their spectral output occurs.

05-30-2008, 11:47 PM
Ive heard that the light output getting dimmer is only a very little bit, and wont matter if you have a hood witha good reflector. Not sure how true it is tho.

05-31-2008, 12:58 AM
I think it's mostly I change in the kelvin rating, although they do dim a little.

If you have a 10000K bulb, for example, over time it could get down to 7000K or so. This would probably change the color of your corals, and could cause an algae bloom if it got low enough.

05-31-2008, 05:09 AM
So it isn't fatal to corals if I don't replace the bulb?