No. Like I say, he is rather cryptic and encourages me to find out things for myself but puts me on the right path. He knows his onions and I have had enough experience with him to know I do not need to double check what he says, although please feel free yourself as you do not have my years of being impressed by the subtle and cryptic guidance.
I don't think a particular brand matters. He was talking about alcoholics and the way that even though they are taking in enough calories, they have thin arms from malnutrition. He particularly said about them having a B12 deficiency because the body prefers to uptake alcohol over B12.
In that context, asking the brand of alcohol or type of product with B12 does not matter, it is something that will happen no matter the brands.
He then went on to say that the CalMag products, and particularly the mono-element products I was buying are very very strong, even though the percentage number on the bottle might not be a very large number and this was a place to look.
As I say, I have now removed 90% of the Ca and Mg from my system (they are probably chock full of those elements now), I am now just giving them part A and part B (and some silicon) at a lower strength and they have started eating again at the rate I would expect for this stage in flower. Since the other day I have increased the food from 300-400PPM. 2 days ago they did not want to eat at 350PPM, now they are eating at 400PPM so good signs.
There are places I would investigate for more knowledge, like which particular elements can interfere with P uptake at the root surface and so on but for a solution, he seemed pretty product agnostic and it seemed the advice was mostly to just put less in.
To really know what is going on, and which changes are the ones responsible for the negative effects they need to be looked at in isolation. This is not really possible in a live system that is not set up like a scientific experiment.
So we must be like Dr House and treat for something and use that as a diagnostic tool with the logic that if the treatment works, we have found the problem.
I have treated for an Mg def and this made things worse. I will be going back to basics, lowering strengths, just putting in A+B, silicon, and maybe a bit of root stim/boost with minimal CalMag (I will probably go back to CalMag over mono bottles now I am sure this is the wrong area of investigation)
I will be starting at a level of CalMag where I should expect a deficiency over excess and I will only increase the CalMag if they show certain signs of Ca of Mg def.
I have tried a few, the mixed ones made my plants go dark green from the nitrogen but I think that was because I was putting too much in. I have not found a mixed CalMag without N in it so I went to the mono bottles with zero N in and my plants have still gone dark green from having the PH too high chasing a non-existant Mg def...
All this leads me back in a big circle to just putting less in and keeping my PH lower.