I have looked up Leaf Zone - and cannot find the specific ingredients, but the general ones look ok.... It does seem to be made to be compatible with fish....so I see no problem with it.
Inever had any difficulties with plants growing well - the nitrogen cycle provided plenty of nitrate - and they like the ammonia and nitrite, too!
I do not grow aquatic plants now, though.
I am going to move this to plants for you and perhaps someone with more specific knowledge will answer.