Post some more info, like medium, feeding/water schedule, and what you are putting into it. That should get you more adequate help here.
Does not look like a zn problem to me, but that analysis is based only on what you have provided. There is no real way to tell unless (we) know what is going into your plants in the first place. Your problem could very well be from lack of/improper food, or even as simple as a ph issue. Again, I really don't think there is such a thing as giving too much information when making a diagnosis. Help me help you.
Read more, and be careful what you feed your plants, and always make sure the ph is okay. Those plants look relatively healthy, so my advice would be not to make any drastic changes.
Practice makes perfect.