600w hps

my hps throws off some heat and was wondering how close i should have it from top of two week old seedling also will it strech useing this light

@ two weeks old I'd have that light at about 3.5 ft. Should start it at about 4 feet and move it down slowly until it's at 18 - 24 inches. That should happen right around week 3 or 4 when the plants have a full 4-5 nodes and are looking pretty hearty. If they start to stretch, move the light down.