24/0. Under 1000w Halide-
Hortilux Blue, or MassMedicalStrains 6000k Halide.
From Starting when they first pop up- Seedling on, they get 24/0 1000w, at no more than 20- 24 inches. Temps 72f-86f.
Though, every 4 days, I turn the light out for 4-6 hours, to let the equipment/bulb cool off. Its recommended to shut the bulb off at least 4 hours, every week. So I do it every 4 days. Been doing 24/0 since they first came out with 1000w Halide, in 1977.