Just coming back from a mid flower PH lockout of my medium a couple weeks ago. Signs of N and Ca deficiencies very apparent. On the mend and recovering now. Leaves are getting green again. Also, I didnt know the leaves would actually heal in the "rust spots" and return to a healthy leaf. Interesting! Anyways, feed ur plants just plain water every 3rd feed and you wont end up in my predicament. Ah well lesson learned.