I am no expert but the typical prescription for Potassium is about 750mg. I take one a day or every other day.
I also have started taking vitamin E when I realized my blood would hardly come out when I was checking my BS. I was very dehydrated. I'm not diabetic or pre-diabetic but I just check. What I did was to begin drinking 1 gallon of water daily and taking a vitamin E (it thins the blood)and saw my BS drop by 20 points and blood pressure down 10 points or so but it was never over 115 before.