Leaves changing colour

If you're using Biobizz (BG/BB/Top max) as you see in their schedule you need to use at least 1ml*L of BG till you flush the plant (In high EC soil, in mid-EC one you can raise it up to 2-3ml) but it totally depend of how your plant say trough its leaves. If you're in 6th week, you should use at least 1,5~2ml*L of BB, you can do incrementals as I do, this is a safe way to nute your plant and avoid overfeed them. You can use top max at 1ml*L till the plant stop strech, then you can go 2 ways, incrementals till max dosage in the last 2 weeks or use it as schedule recommends, it have trace elements (Mo, B, Zn, Fe) but almost 0,1% of NPK, so the overdose with this product is nearly imposible.