Good day my friends Scotty, Dude and Guru. Please help what are my possible problems here. Week 4 flower. I have some of what looks like rust spots on my upper oldest growth. Nothing past about 6 inches from the top. Growing 1 beautiful girl in 5 Gal coco with very little perlite, using emerald harvest nutrients about half strength, with full strength cal/mag and Recharge every two weeks. This is a new problem just happened 4 days ago. What could have caused this? I think I let the media dry too much or my pH pen kicked the bucket.