This is the way to do it; experiment and find out what suits you. There is no fasit for Borax use nor Iodine:
but it is helpful to hear about other`s experience.
My gardenias get a pinch of Borax in their water once a week now; they have never looked better!
I have a couple of new experiments going with borax; very promising but to early to make a conclusion.
One involves a cat with dandruff; he is better, maybe as much as 30 % better in two weeks. His coat is shinier ; the same happened to the plants; leaves got shiny after just one night with borax.