People, and this includes myself, have spent A LOT of time identifying deficiencies, like it's the most important thing to know what exactly the deficiency is. IT IS NOT.
Why? Because in almost all cases, be it some type of def (or toxicity), regardless what it is, the solution is the same:
You will flush your plants with pHed water with the correct pH (soil: 6.5, hydro 5.5-6.0), and then give nutrients in the appropriate dosage. What *exact* deficiency it is/was is not even that important. (The other issue is, many deficiencies come in a combo, so the symptoms can include signs of all sorts of deficiencies and are not always that clear, even for me as an "experienced" grower.)
Most deficiencies/toxicities come from incorrect pH anyway. (Eg. watering with non pH-ed water, or overfeeding which accumulates salts in the soil so that the pH is off after some time, leading to deficiencies).
Flush --> (to correct your soil's pH) ---> water/feed with correct pH ---> 99% of all problems are solved.