Ligthing for 2ft deep tank


I want to make sure I got it right and hope knowledgeable peoples
on this list would help. I'm doing preparation for the 2ft deep
120gal tank I'll be getting in the next few months. I was reading
the august issue of Fishkeeping Answer (a British mag) and they
mentioned that only MH or MV lamps are recommended for 2ft or deeper
tanks. Flo tubes are for depth of 18" or less. Is this true or could
I get away with only flo bulbs? As the lighting would be costly, I want 
the lighting to be absolute and would not want to have to change it 
later on. Thanks in advance for any help.