Help me please! Light distance from plants?

I have 2 plants inside my closet growroom, and i am using a 100w Sodium buld plus 2 enviro's. As it is such a small growroom that is why i have such a small bulb as it would fry the plants.
My light is hanging 17 inches away from the top of the plants that are 8 inches tall each.
Is the light close enough to the plants or too close?
Also my 2 enviro's are hanging down but about an inch away from top of plants.Please advise!
All suggestions are welcome!
Plant the seed and free the Weed!

Get it as close as possible without burning the plants, if you have good ventalation, you can get them closer, i had a branch grow 3 inches from my 400w hps bulb, it didnt start to burn until it got to 2 inches, then i had to rotate it away from the bulb. a fan was running constantly on the area this happened.