I always get this with biobizz, I think It's N def, as biobizz is organic it takes time for it to "work " in the soil and so if the plant gets hungry all of a sudden, which mj does then it's no good. The bottle says to use up to 4ml per litre, and even that wasn't enough. I moved on to full strength growth technology - chilli focus and it clears it right up fast.