5sackanswered grow question 6y ago Potentially an Issue with recent Phosphorus uptake coming into the Bloom stage. Excessive amounts of Phosphorus is relatively common especially during flower, Symptoms show as micro-nutrient deficiencies in the form on Zinc & Iron. ( Which personally was my 1st guess after taking a glance ). With your stable pH, Phosphorus availability increases & lowers Calcium & Magnesium's availability within the medium. Attempting to Leech out the Phosphorus is not personally recommended as it can change its form and combine with Calcium to create Insoluble Compounds. Try raising your pH levels and be sure to Leech very well with plain water a few days before harvest. Best of Luck!!