150W HPS Sun System Noobie! NEED HELP! WITH THIS PARTICULAR LIGHT!

So i just bought a 150w HPS Sunsystem lamp...
http://www.hydrowarehouse.com/images/sunlight-sun-system-hps150.jpg

and i need 2 know if anyones had positive results using this lamp, and if so HOW FAR DO I NEED 2 HAVE IT AWAY FROM THE TOPS OF MY PLANTS!?!?!?!

sorry for the caps but ive already had 4 clones die on me, i bought new ones 2 today!

Light should be fine for 1-2 plants... as far as your clones go, if they are fresh clones you want to put them in a humidity dome and get the root systems going well first. you can hang this light over the dome, I would say no more than 12 inches... once the clones have rooted well you can then take them from the dome.... The rule of thumb for lights over plants is hand test. put your hand above the top of the plant, if your hand gets hot then move the light up until you hit a happy spot.

the clone i bought is about 10inches tall :/ what do u supose i do!?