Your previous statement was "The experiments with CHC suggests that it will preferentially hold onto K and Na over Ca and Mg" Now you are saying the opposite.
Yes, on rereading my post I see I have fallen into the same trap as equating the cation exchange capacity (the resin element) with the chemical reactions between the phenolic matrix and Ca/Mg. This was not my attention. Rather, what was meant, is that the experiments/experiences are that the resin-character of CHC will preferentially accumulate K while absorbable Ca & Mg is either washed out or (in the case of Mg) its absorbence in inhibited by the uptake of K. This is easy to see on mediums. Ca/Mg phenolic salts are brown in color but the salt building up on organic mediums tends to be white---K and Na salts. It is these salts that accumulate in the medium.
But this discussion is useless. I have previously proposed a testable hypothesis in http://www.slippertalk.com/forum/showpost.php?p=427088&postcount=23 which was that: by feeding low-K fertilize the excess of K in the substrate is avoided and the plant can assimilate sufficient Mg and B.
Leaf/stem analysis of plants fed high and low-K fertilizers should find that the low-K plants have more Mg and B than the high-K plants. Testing the hypothesis is the only means to arrive at any certain answer. This philosophical banner is of no use for we have no certainty over the various claims. What we do have are lots of people who have switched to K-light and have seen improvements in their plants. I was looking at my Seagrow fertilize this morning and notices that is a K-lightish fertilizer with 70 g/kg N but only 15 g/Kg K (with 0.5 g/kg Ca and 1.7 g/Kg Mg).
Unless we do the experiment we can argue forever and not get anywhere.
And for the last TIME the Antec site is NOT the reference for CHC holding onto K preferentially to Ca/Mg. I am still trying find that reference again.