When I plant seeds, some just don't thrive. One local radio garden expert says that the only thing he's seen that will bring almost dead plants back to life, is to spray them with seaweed extract! Interesting.
I believe we're on the right track with Iodine/Seaweed. Living on a poisoned plant, that's something really positive.
As you point out, we each have to do our own fine-tuning. That's the hard part.