I was running 1000 HPS in 12/12. It was too much. I couldnt move the light high enough, so this time i decided to put it on the 600 setting. DLI doesnt really mean thats all the light it can handle, and its done for the day. Otherwise you couldnt veg it 24 hrs a day. DLI is a preference of the plant, not a maximum. I wish i had a well spread LED light instead of HPS.