Your leaf damage appears to be from a phosphorous deficiency.
You want pH 5.8 for hydroponic and soiless (peat moss and coco coir) and pH 6.5 for soil.
Here is a nutrient availability chart
Here is a cannabis leaf deficiency chart
here is the Cannabis Plant and Pest Problem Solver and the Plant Abuse Chart
Cannabis Plant and Pest Problem Solver: Pictorial
Plant Abuse Chart
You want pH 5.8 for hydroponic and soiless (peat moss and coco coir) and pH 6.5 for soil.
Here is a nutrient availability chart
Here is a cannabis leaf deficiency chart
here is the Cannabis Plant and Pest Problem Solver and the Plant Abuse Chart
Cannabis Plant and Pest Problem Solver: Pictorial
Plant Abuse Chart