First grow. Golden Lemons

If your using sun system then 24-26 inches and further for seedlings probably around 30 inches. But different models of cmh need to be hung different. Some at 3 ft. Same as with MH/HPS grow lights, always conduct the 30-second “hand test” after you’ve positioned your light. If the light bothers your hand after 30 seconds, it may bother your plants!