Lighting 101?

[Scott Rossi <srossi at scottrossi_com>]

Hello,

Hoping someone can shed some light on the subject here.  Everyone is saying
light, light, light.  Now how much light is needed?  

I have a 46gal bowfront with 2 daylight lamps and a 50/50 all rated at 30W.
I have a huge problem with algae growing on the leaves of my plants.  I have
a co2 injector and all sort of algae eaters(SAE's, Shrimp, Otto's, etc..)  I
leave the light on about 12 hours a day.  Substrate is 100% fluorite with a
tiny layer of laterite.  The substrate depth is 4 inches.  I do not add any
fertilizers to the water column and only feed the fish once per day to force
them to eat the algae.  

Water temp = 82
PH = 6.8
Hardness = 110


Am i short on light? or am I totally missing something here?  

If I add a plant within 3 days it will have a brownish algae on it then it
will turn to a deep green algae and then the plant leaf will actually start
dying after a week or tow.

Please Help.