Well im 3 weeks into my indoor medical grow. Im growing in a 5x5 tent 600 watt hps. I have a 4 in Ventech pulling air out of the tent thru a charcoal filter. Growing in a soil happy frog dirt in 5 gal potters. Using open seamen in beginning then rest will be organic bat guano. My issues are I recently had powdery mildew and spidermites. I picked up a chemical call nuke em totally killed my powdery mildew and spider mites. But now I'm noticing quite a few leaves are turning brown and crisping up. I dont have a magnifying glass so I cant get a good look to identify the problem. If anyone has any ideas as to what this could be and how to resolve issue would be appreciated. My airflow is decent somewhat of a passive intake as I have no fan pushing fresh air in only have vents in bottom of tent which air gets pulled in from. Also have window open in grow room so fresh air gets inside room. Any ideas? Will post pics soon