I thought it was phosperoous and chased that...
The cal mag was added by fluke becase i heard cob guys really have to watch that.
Cal and mag are immobile and i wonder from recent experience if that is related somehow to phosperhous deficency???? IE....i had bad phosperous deficeny last run....was classic...all the signs....then BOOM! All of a sudden cal mag deficeny was all over and FAST...and bad....
Crippled my yield....
I thought i might have had salt build up and lock out.... but im ususally really carefull about that