hey there that's a magnesium issue , probably because this pheno is more sensitive to the light schedule , the temperature , or even the pH. You can tell based on how the leafs are yellowing between the veins of the leafs, just add cal mag to your feed and as a spray twice a week at the same time as the bio roots. The problem will stop spreading immediately and the plant should recover in ten days or less . Hope this helps ! 🚀