Thanks to some reference work on this thread and into my archives, I have nailed this down to Ca def. Run off was testing a little low far as pH goes. I under-shot the lime and gypsum in this soil mix.
3-pronged attack, pH buffered waters, CaMg+ (already gotten onto both) and a little feed with molasses next time they get thirsty. This is the worst leaf. It became pretty easy to figure out as soon as I had them out from under the HID. The sprays were doing a little to help this on and colour the necrotic spots, which was causing the confusion. The little yellow 'corona' around the spots are a dead give-away, also the 'isolation' of the dead spots in the middle of the leaf. My dirty hippy just been in the dirt thumb is in there for scale.
On most of the leaves where you can actually find signs of this, there are only the smallest of little deadening spots, about 1/4 the size of these on this leaf, and a tell-tale 'patchy' yellowing of the front left 1/8th of a single finger on girl no 3.
Gandalf, it was your post revisiting your pH and Ca issue that prompted me to cross-reference this problem. I am now 100 percent sure. Thanks mate. In sharing our weaknesses we make the whole group stronger. Learning from each other's lessons. The Circle Of Green continues...
At least my least favourite pheno got this first and gave me warning before the others suffered. I am having the best luck with this run. Badasssss.
