Lighting: Duration vs. Intensity

According to the formula in the Plants FAQ for calculating the optimal
lighting intensity and duration for different plants/tank setups, I need
to leave my lights on for 13-14 hours. In a recent post, George Booth said
that he only kept his discus tank on 9 hours a day due to algae problem. I
also want to keep algae under control. My question is: does algae like
more intensity or longer duration? I currently have two double fixture
shop lights with two Tritons and two Ultralumes. I think I can add two
more single flourescent fixtures to my custom hood, but I am concerned
that the algae problem would get worse. Do you think adding two more lights
(+80watt) and reduce the duration (9-10h/d instead of 13-14) would reduce
to increase algae growth? What about plants? 

If I do add two more lights, can I just use cool white bulbs for the new 
lights? Not sure if I can keep up with these $25.00 Tritons...

 John Y. Ching (jyching at watnow_uwaterloo.ca)    |
 Pattern Analysis and Machine Intelligence Lab	| 
 Department of Systems Design Engineering      	| 
 University of Waterloo, Canada            	|