Your tree looks fantastic. There is probably no problem. However if it is greening your tree has no choice but to bend over and kiss its rear goodbye. I wish my trees looked even close to that.

It looks pretty good.

@ poncirusguy, OP is in northern CA, no citrus greening here yet.

Yeffi, you say you "recently fertilized, added azamite, epsom salts, and iron/zinc", does that mean you added a complete fertilizer, AND added azamite, epsom salts and iron/zinc, or are you saying the added azamite, epsom salts and iron/zinc IS the fertilizer you added?

I ask because, the only problem I see is the new leaves are a bit all-over lighter green, which can be a symptom of Nitrogen deficiency. Young leaves are often lighter green than the mature leaves, but if they don't green up by the time they are full sized leaves then it may be a nitrogen deficiency.
The products you listed are all micro-nutrients and minerals; they don't contain any nitrogen, so they wouldn't help your problem.
I'm not a fan of epsom salts(Magnesium sulfate) anyway as both magnesium and sulfur are included in most good Citrus Fertilizers, and a complete fertilizer has the micros and macro nutrients in balance so one does not adversely affect another.

I think the horse manure had the nitrogen your citrus needed at first, but it does get used up and so after about 6-8 weeks the nitrogen was gone. Plus with that much watering you will need to feed more often.

If your soil drains well enough, and as the tree looks healthy, it probably does, that amount of water in the heat of summer is fine, but you do need to feed more often when you water more often.

I would get a good complete citrus fertilizer, (not fertilizer stakes though) and use it according to the label. Ideally you should be fertilizing at least every 8 to 10 weeks or even more if the label recommends to.

Overall though, except for being a little nitrogen hungry, it's looking very nice!

Also, the patches of yellow on the couple of older leaves could be either a bit of sun scorch (we've had quite a few really hot days lately, I think I'm near you, I'm in Cupertino) or what happens when the tree steals nitrogen from older leaves to supply it to the new growth. They will do that if they're hungry, sacrifice the older leaves for the new ones. Another clue it's hungry for nitrogen.

I had a similar problem last year with my then three year old red grapefruit tree. The leaves were all yellow and falling off and any flower buds just fell off. I watered the base of the tree with a solution of chelated iron and also watered over the leaves. Eventually the tree recovered and the leaves are all green again.

I have been using 7,3,3 E.B.Stone Organic Citrus and fruit tree food. I have been told that the organic citrus food does not come with the trace minerals. This is why i was adding the other trace minerals. Although Azomite is supposed to have all the trace minerals, i have not found any information about how much to apply and how long it takes to break down. Both old and new leaves have a nice dark green color. the yellowing is only on top layer leaves, so i am leaning towards sun burnt as the pattern is so unsymmetrical. but, with plenty of water, i thought citrus could withstand the sun. perhaps it is the concrete driveway near the bed that is causing my problem?? thoughts?