Fellow Growers, The Grow Box is making my plants grow much better. However I am still having black, dead leaves and discoloration on others. Apparently a residual, left over problem from the pre-go box days. But a friend who runs a feed store said "yellow leaves? that's a lack of iron" I looked at their iron, a bottled nutrient and 10-12 ounces was $50. About minerals, I looked at the labels of all my go box nutrients and no iron. Hey, since my water is rain water I am really studying minerals for plant growth. The iron at the feed store had several other minerals as well but I don't want to mix nutrients without knowing what I am doing. Why isn't their iron in the go box nutrients? Or is the calcium and magnesium in Cal-mag judged enough minerals for cannabis? My plants are really growing but for the few dead leaves and the discoloration on 10% of the leaves. Might it correct itself after a while? I don't give the plants any water without cal-mag because of the lack of minerals in rain. I'd haul water except it is so heavy. Anyone ever had this problem? I'll figure this out or just buy spring water. Thank you... The Poet... .