A light meter is really the only way to know what were dealing with here.
It's on my wish list.I really doubt T8's are twice as bright.

In reef tanks 150 watts double ended HQI bulbs were said to be brighter than
175 watt and even 250 watt mogul bulbs. This was proven not the case.

I do agree 3 watts per gallon is ideal with power compacts atleast. It has
worked well for me.

Drew


"Dave M. Picklyk" wrote in message
...
I've been doing some research and a lot of people are saying that the
watts
per gallon (wpg) rules for adequate lighting are becoming useless because
of
the newer T-8 slim flourescents compared to the older T-12s.

In fact, one person said that with a light meter they found out that 4 T-8
bulbs put out nearly twice the light of 4 T-12 bulbs! Some people are
saying
that the quality of light is better: they can produce a broader spectrum
of
light.

SO! Do I actually have good enough lighting with 2wpg as T-8 bulbs?? I
currently have 1 LifeGlo 15W and 1 PowerGlo 15W for my 15 gal. (most
people
say that 3wpg is more the idea lighting).

And the bonus, T8 is more efficient (run at less current but higher
voltage
then the T12), puts out less heat, degrades light intensity slowly over
time
and to a lesser extent.

Any opinions?