Lights how high

Approx. how high should my lights be from my plants. I'm on day 4 after planting and the lights are 16" high.
150w Sunsystem HPS
I read somewhere to lower the lights so that the plants don't stretch too much.
I'm currently growing in dr60, so im limited on space.
Thanks

There's a handy-dandy light distance chart on this thread that might help....

https://www.rollitup.org/grow-room-design-setup/354761-light-distence.html

lower the light until it is warm on the back of your hand when you put it to the top of the canopy.

when I started off w the exact same light, I got best results at twelve inches in my closet, but 16 in (right where youre at) in my dr 80 (w a fan blowing at it). heat became an issue at 12 inches in the tent. hope that helps a little