I dont have experience with those nutes, but I did a google and found two links that kind of reflect your problem. Both said mg defiency or ozone problem, as if you were to have one of those generators for smell..

Brown Spots On Leaves!!! (Pics Included) - Hip Forums



For the 2nd link, a quarter of the way down is a description
Marijuana Plants Problems - Yellow Leaves, brown spots, nutrient shortage etc.