Personally looks to me like you waiting a tad to long to start feeding nutrients and theres a little deficiency coming through, the yellowing leaves at the bottom seems to substantiate that. Look up a feeding schedule for your nutrients, I use future harvest and they have a week by week chart I use (tweaking it occasionally). Watering every 3-4 days 500ml seems light to me. Once my plants are about 6-7 weeks I’m watering 2L every second day and they are dry by the next watering. My environment is 75-80f and 40-50% humidity fairly consistently.