OG Kush first time growing (need some tips)

try some cal mag for the yellowing, to clean your roots , feed them regular ph water with some flush solution . You can try more water soluble nutes , usually the clear bottle ones with no sediments swimming around, look like colored water/juice

Also in between each feeds u can dip your roots in clean ph water

dude chill my plants are in hydro my first grow. i have a waterfarm though. my roots have looked like that since i added nutes. and its doing fine and plenty healthy. in 5 weeks flower now. i wouldnt worry about it.