I would say that reducing, first and foremost, N and P content of soils is of the utmost importance. Vulx has a special affinity for these, and high Brix is a result of good soil balance, so too much of Vulx's most-loved cations would throw off nutrient ratios in plant tissue.
Thing is....my soil has the perfect amount of N and P.....it's designed that way. We shall see!