The fish will be fine with 3 lamps running, the only thing that may be of concern is the dredded algae, but with enough co2 injection this should not be a major issue. As to the light control unit just sit it inside the hood somewhere if there is room, one of my control units is sat to one side on the tank, as i have no room inside the hood with my t5 unit, hope this helps you Stella
Cheers Gordon
Cheers Gordon