I used to use Leaf Zone in my first planted tank. It only adds K and nothing else from what I remember. There is nothing that should be harmful in Leaf Zone as most fert regimins contain the same as Leaf Zone plus some.
Tom Barr has made a few comments on the subject. Just don't go overboard.
A forum community dedicated to Aquatic tank owners and enthusiasts. Come join the discussion about flora, fauna, health, housing, filters, care, classifieds, and more!