i agree with all you said. i have grown plants that required a lower ph and when i discovered magnets, i was able to keep the ph down using positive(south pole) magnets and no longer needed to compensate chemically, even after weeks had passed and the ph should have been sky high. this would account for different plants liking different poles because of different ph requirements. therefor, another positive effect of negative(north pole) magnets would be a tendency to produce an alkalizing effect.