Few questions!

lighting: electric sky 180v2
lighting distance: 37in (lowering as needed)
fan: cloudline t4
tent: 2x4
soil: Fox Farm ocean forest soil
water: distilled ph’Ed around 6.4-6.6.
strains: northern lights auto, candy kush auto, and tangerine dream auto
One question I still have for this grow when do I start adding nutrients to my soil?? I normally test my run off but was confused my last grow. At what Ppm range from the soil should I start adding in bottles nutes?? @Mr. Grow It
Thanks for sharing your experience.