I have made my own many times before. I've used CS for over 10 years, never had a problem. It is fine for external use. Unless you have a way to determine PPM would use a good quality for internal. I keep 10ppm, 30 ppm, and 500 ppm in house at all times. It is antibacterial, not antiviral. I have used it in my eyes. I also have put in in my dog's water to help him .There is a difference. It is not hard to make your own.