Re: T8 vs T12

>T-12's are the common, 1.5 inch diameter fluorescent lights.  T-8's are
>only 1 inch diameter.  They are brighter, and you can pack them closer
>together.  I made a light fixture for a fifteen gallon plant tank that has
>four two foot T-8's, run by an Advance electronic ballast (REL-43P2-RH-TP).
>This ballast can run 3 or 4 T-8's, which can be 48 inch, 36 inch, or 24
>inch bulbs.  It cost me around $26.00.  Using a light meter, I found that
>the four T-8 bulbs put out about twice as much light as three T-12 bulbs. I
>agree with Karen.  T-8's are definitely better than T-12's.   I have plans
>to replace the two T-12's on my 55 gal with four T-8's and the four T-12's
>on my 75 gal with eight T-8's.

As Karen mentioned, you'll get the best results from T8s when you use them
with electronic ballasts. T12s cannot be driven by electronic ballasts. T8s
produce more light with less energy than equivalent length T12s and the
energy savings come from both the lamps and the ballasts.

Electronic ballasts also allow you to hook up lighting controls such as
dimmers with which you can simulate sunrises and sunsets.

I'm really surprised at George and other's measurements of the lumen
depreciation from their fluorescent lamps. There must be other factors at
work because commercial places certainly don't need to replace their banks
of fluorescents every two or even twelve months. I know of one
energy-efficient lighting scheme in which fluorescents are driven at higher
than their rated wattage. The result is even more light output without a
significant sacrifice in life. Of course, T8s and electronic ballasts are

Greg. Tong
gtong at sirius_com

"Often, the things that change are less interesting than those that stay
the same."--Aaron Fleisher