Mix water and providence, dip sea sponge in mixture, insert and leave for 10-15 minutes, 3 x daily. End of yeast. Make 20-30 drops per 1 oz water or more, I go by color. Like it to be darker than pee. Start with a little and slowly increase with each dose in case you have a lot of dying off...
Provi done, this machine keeps changing the spelling. Use Lugols if you can afford it, but P. is cheap.