Re: KCl, you get what you pay for and you can't overlook the fact that 2ppm Cl is all it takes to "nuke" microbiology. You can ask any municipal water system manager for confirmation in problem city wells.
Soil Health is much more than just what fertilizer you select.
1. Chemistry - Anything applied to the soil; i.e. fertilizer, etc. 2. Physics - CEC or the composition of the soil (sand, silt or clay). 3. Microbiology - the life in the soil.
All are equally important and must be considered when making fertilizer plans.