Re: lighting question

>From: olga at arts_ubc.ca
>Date: Tue, 3 Dec 1996 15:58:50 -0700
> I want to buy the appropriate T8s with the appropriate balast. I have a
> great commercial place to go but I want to be able to walk in and ask for
> them without humming and hawing. So just what do I ask for? Oh yes, this is
> for my paludarium so I just want two 48" florescents.

If I were in your shoes, I'd pick the bulb first - preferrably a full
spectrum bulb with good lumen (light output) rating.  Then I'd choose
a ballast that goes with the bulb.  If there is a choice between
instant-start and rapid-start ballasts, I'd go with the instant-start

If you want to get real technical, ask if they have "ballast factor"
ratings for the ballasts (they probably won't).  A higher ballast
factor means that the ballast drives the bulb harder, making it
produce more light.  Another choice you may have is between parallel
wired ballasts and series-wired ballasts.  With paralle-wired
ballasts, if one bulb burns out, the other will remain lit.

>  And -- I have 4 T12s at the moment running off a electronic ballast over
> my 48 gallon. I presume that I can replace the T12s with T8s with no
> problem.

You should take a look at your existing electronic ballast before you
replace the T-12 bulbs with T-8s.  If your ballast is not rated for
T-8 bulbs, you will need to replace it.

The benefits of your proposed upgrade are not obvious to me.  In spite
of the positive comments of some people on this list, the material I
have read says that the average T-8 bulb is not brighter than the
average T12 bulb.  On average, T-8 bulbs produce about 8% less
light. However, there is a lot of variation in the light output of
different bulbs, so the actual lumen ratings of the T12 and T8 bulbs
in question should be an important factor in deciding whether a
retrofit with T-8 components makes sense.  Other factors are the
energy savings (about 20%) and cost.