Yellow spots

Get your pH slightly acidic - <7 It might be a sulfur-toxicty.... Bringing the pH under 7 may fix it... As you reduce pH, sulfur is less available to the plant for one reason or another. leaf septoria concern: Also, do you stick to a wet-dry cycle? allow 1" to dry before irrigating. feel weight of pot -- learn what dry feels like. Make sure you get some runoff you ensure no dry pockets. if late in grow and not some super soil type setup, feed full strength with 20% runoff to ensure proper fertile substrate, no buildup... proper ratios maintained. it's true that soil can self-correct pH a bit, but why push it.. leave that for problems you can't see... a safety net rather than all-in. even water-only irrigations should be pH'd to ~6.8. Your ferts should be pH to 6.8. A little ebb and flow is fine. get the pH in order, if you weren't doing a wet-dry cycle rootzone issues could be the cuase, like leaf septoria.... see what happens with these 2 courses of action before changing any mixtures.