You ingest it?
500 ppm, what amount and frequency?
500 parts per million (potency)
A normal dose would be 1/2 teaspoon in 6 ozs. of water once a day in a GLASS container. (do not use plastic)
If I’m sick, I double the dosage to twice per day. (you can also double the dosage)
If you get it from http://www.herbalhealer.com/ they provide instructions. (it may also be used topically in ears, nose, wounds, etc)