I think nutrients in general cause more problems than we think. I have 2 sour livers going right now on the same feed. One has slightly burnt tips and just started showing some yellow. The one without the burnt tips is green and healthy. Organic grows always seem to be the healthiest and I think it's partially because the slow breakdown of nutrients vs the quick delivery of bottled synthetics. Organic grows also show much more trichomes and I think it's because synthetics seem to cook them right off.