Fluorescent Bulbs

[stanton9202]

I was at the LFS yesterday and one of the employees told me that fluorescent bulbs are only good for about 6 months before they lose something and aren't effective anymore.

Has anyone heard of such a thing?

Thanks,
Stan

[Harry Tolen]

It is true that fluorescent bulbs begin to shift their emissions patterns significantly after about 6 months. However, this is only important if you have a planted tank with very demanding plants. For fish only, or for fish with low-light plants such as anubias and java fern, there is really no problem as long as the bulb continues to work.

Other thoughts/comments, as always, are welcome.

[predatorcichlid]

Yes, they do have a service life. This depending on the quality of the bulb, what type of flourescent bulb and type of ballast is in used. A cheap set up with a cheap bulb will only last about 6 months. A high quality electronic ballast with a research grade bulb will last a year. The higher quality set up's will burn within there specific lux, color, and temp range better and longer, not to mention creat less heat. HO and VHO bulbs will provide far more lux per watt and when set up correctly with reflectors and electronic ballast can last up to 16 months. These figures will vary depending on how many hours a day the bulbs are in actual use.

[stanton9202]

Thanks.

It's the original bulb/ballast that came with a 46 bowfront made by AGA. It's about a year and a half old.

[a_free_bird73]

The useful life of a bulb also depends on the size (in addition to quality). Check the life specs and divide by 2 is the rule I use. With standard fluoro's you will find that 4 and 6 foot lights are rated for 20,000 hours (~4 years, 12 hours per day) but I only use them for 2 years. 3ft are generally rated 9,000 hours (useful life about 1 year) and 2ft are rated 7500 hours (useful life around 9 months).

Compacts have similar size based specifications but I don't know the number of the top of my head because I don't use them.