My plants are 6 weeks into flower. They are 95% yellow now. I recognised it to be a nitrogen Deficiency around 1.5 weeks ago because the shop I bought my set up from told me I was using the wrong nutrients (their advice!!). I've bought the correct stuff now containing nitrogen and potassium and all the good stuff and started adding this 1.5 weeks ago but have seen no change. Any advice? Are the leaves all too damaged and as such are irreparable, so new growth will be the only stuff which shows signs of green? What will the effect be on the strength and yield?