I was useing a 600w hps at two and a half feet the other day and still managed to burn my babies that was with a fan as well.. Are you controlling the heat, If so and doing it really well then 2 to 2/12 feet would be fine i think but please dont qoute me on that as ive only just started growing my self thats just what ive learned might be right might be wrong..Plant is 11 days old been under a 1000watt for 3 days now at 3 ft. how close can they be from it???? 2ft??
my um gallery has the pics oh here they are like these...Are you using MH or HPS lighting? You might want to fab up a cooling tube of some sort, so you can get the lights closer.