Lighting Intensity

After recent discussions with fellow APDers offline as to the benefits of MH vs. standard
flourescent, I thought that I would post my experience to solicit responses from the

Question One:  Is it true that the intensity of MH is the same as 4 flourescents at the surface
of the aquarium?

Second Question:  If question one is true, does one form of light penetrate water better
than the other?  IOW, should a tank that is lit by flourescents be more intensly lit at the
same depth as light from a MH bulb?

My experience would indicate that the answer to question number two is yes.  When I worked at
a pet store a year ago, the owner had a device that measured lux.  We tested it on two tanks. 
One tank had two 175w MH bulbs, and the other had four VHO flourescents.  Both appeared to
have the same intensity at the water's surface (the VHO was a little less intense), but at a
depth of 20", the tank with the MH bulbs gave a significantly higher reading.  Does this
seem accurate, or does everyone think that I was smoking my aquatic plants?  Could this
effect have been caused by the type of reflector or the differences between MHs and

What is the collectives opinion on the benefits, if any, of going with MH?


Eric Schoville
eschovil at us_oracle.com 

"The swift bird flies alone.  A solitary mien has no companions."