Re: [APD] Old Ballasts?

["S. Hieber" <shieber at yahoo_com>]

I think it's hard to say from the info on hand.  

Genaralizations that might apply: Electronic ballasts, like
all electronic devices can fail due to the unpredictable
failure of one or more of its components.

The life of bulbs is probably more unpredictable -- rated
lifespans are estimated averages based on samples from
production runs made to the same specs. Two bulbs from the
same run operated on the same ballsat might fail years
apart.

Early failure of a bulb, if caused by a missperforming
ballast would proably be due to the ballast overdriving the
bulbs -- they would run significantly hotter than normal
and would blacken at the filament ends of the tubes early
and more severely than normal for bulbs of that age.
Moderate overdriving isn't something to be concerned about,
imo; ballast and bulb designers don't expect exact matches
between bulb and ballast and some tolerance is built into
the specs.

But yes, you could have a bad batch of bulbs. Without a
meter to check the voltage of the ballast output, which
could be compared to a normal value for that ballast, it's
hard to assess the ballast except to do as you have done,
try it with other bulbs. If bulbs appear to light normaly
and run no hotter than normal, the ballast is probably okay
and you can blame the bulbs. It is normal for fluorescents
to bulbs to blacken at the ends as they age. Any time they
are lit, the filaments are slowly vaporizing. Starting the
lamps probably causes more vaporization than running the
bulbs for several hours -- but aquatic gardeners cycle
their bulbs only once a day so cycling isn't likely a cause
of premature bulb failure. 

I would try to keep running the old bulbs on at least one
of the ballasts, and try new bulbs on the other, under the
presumption that the ballasts are okay. If the old bulbs
fail in a few months with severe end blackening, or they
run much hotter than new bulbs, you'll know the presumption
was wrong.

I don't know what size ballast and bulbs you are using but
generally a Fulham ballast can be gotten for about the
price of a pair of bulbs.

Where they AHS bulbs, old and new?

Sorry, I know that's nNot much help,
Scott H.
--- Rachel Sandage <rachelsor at hotmail_com> wrote:

> I bought AH Supply Bright Kits when I first set up my
> aquarium in the summer of 2001. I bought all new bulbs in
> August of '03, and in the past few months 3 out of the 4
> have stopped working - they don't come on anymore, and
> their bases are discolored. The ballasts still work - I
> saved my old bulbs, and when I plug them in they light
> right up - but I am wondering if the ballasts have
> somehow gone bad, or if I just got a bad batch of bulbs?
> I have been totally happy with AHS, and don't know what
> is going on.


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