m0useanswered grow question 3 years ago With super soils its a bit harder to get micronutrient deficiencies.
More likely an issues with macro or environmentals
macro = larger nutrients micro=smaller nutrients
Macronutrients: N, P, K,
secondary macro Ca, Mg, S,
Micronutrients: Cl, Fe, B, Mn, Zn, Cu, Mo, Ni,
secondary micro Si, Co
Giving the spotting it looks like potassium in combination with a bit of calcium and magnesium.
Check your PH/EC/PPM of feed going in and if you monitor runoff check its pH/PPM/EC as well.
This very would could be lockout via salt build up. Let is know your results or attach the diary.
Best of Luck,