Re: T-8 vs. T-12 (Here we go again!)

>For a while now, I've been thinking about designing a new hood.  I've
>currently got two twin-bulb strips, and it's a hassle.  So, I dug
>into the Grainger catalog to pick out bulbs and ballasts.  At first,
>everything seemed easy:
>                                CRI     Initial Lumens  Price
>  Phillips 5000K Ultralume T-12  85          2925       $10.96
>  Phillips 5000K TL850 T-8       84          2950       $ 4.64
>Gee, that was easy.  I *love* T-8s!  Ballasts are cheap, too!
>Magnetek has a 4 T-8 ballast (B423I120RH) for $41.20.  Then I looked
>back at the bulb section, and saw...
>  Phillips 5000K Advantage T-10  80          3700       $10.67
>Hmm.  CRI isn't quite as good, they're a little more expensive, but a
>25% increase in lumens sure sounds good!
>Does anyone have experience with the Advantage bulbs?  Advice?

The lumens you list are "Initial Lumens." Always choose lamps on the basis
of "Design" or "Mean" Lumens. Fluorescents start out producing more light
than they are rated for. This drops off quickly after a burn-in period (100
hours, I believe). What you're left with are design or mean lumens which
should continue for 1-1/2 to 2 years (everything else being equal).

How do your lamps compare where design or mean lumens are concerned? And
make sure the T10 will fit well with the T8 electronic ballast. A mismatch
can shorten lamp life and/or reduce lumen output. Also, the T10 has a lower
CRI which might make your plants and fish look different than under the
other lamps.

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

"Every infinity is composed of only two halves."