Re: How long are lights good for?

George writes:

>The bulbs I use are Triton and PennPlax Ultra TriLux.  They are
>significantly brighter than a typical 40w cool white.  Perhaps the
>extra brightness translates somehow into shorter life.

I think I'm going to stick to non-aquarium fluorescents. From your
measurements, I strongly suspect the aquarium lights are not built to last.

Brightness should have nothing to do with lamp life since the lights should
be engineered with the brightness in mind. I just got some new GE lamps
called SPX50. They burn at 5100 Kelvin--perhaps not brighter than the
aquarium lights but bright enough for my purposes. I got the T8s for longer
life and so I can dim them if I ever get the energy to make the necessary
connections, but they also come in T12 sizes.

>Perhaps the engineering charts don't take into account the fact that
>we turn our lights on and off each day (this shortens the life).

The engineering charts would be for typical use. Offices, shops, warehouses
would turn their lights on and off every day.

>Perhaps the engineering charts don't take into account the bulbs are
>in an unventilated hood and might run warmer than the engineers
>figured on (this shortens the life).

This is possible but I don't think our hoods are that much less ventilated
than enclosed fluorescent fixtures.

>Perhaps the engineers are being optimistic (this prolongs the life :-).

I suspected this too until I found the data in publications that were not
published by light manufacturers. :-) I'll try to get hold of a lux meter
and try some of the same measurements on the SPX50s when I install them.

Greg. Tong
San Francisco, CA, USA
gtong at sirius_com

"Every infinity is composed of only two halves."