Im new to fasting but from what I have seen you need sodium, magnesium, and potassium. Most people use iodized salt, no salt, or baking soda. I think you should be good with that with the magnesium and potassium but may want to also drink salt water for sodium intake. Best of luck with the fast!
That BRAINFORZA formula looks good but seems to lack enough sodium and potassium for a water fast of more than 2 days.
Morton Lite Salt has sodium chloride, potassium, calcium, and magnesium. A half teaspoon of that and a squirt of lemon juice for taste (in 3 liters of water daily) is what I have tried during my first 5-day water fast.