Calcium
Following up during a phone call to BAS, they suggested I try this Gypsum to add Calcium to a mix which was my third run in 15 gallon containers. I had "re-amended" with a combination of Coots mix and Oly mountain plus added worm castings when I transplanted. But there was signs of yellowing and overall "exhaustion". Adding the Diamond K definitely helped green them up after two weeks or so (using a blumat system via top dress makes a bit slower intake/uptake).