You could order oral rehydration salts in 1 oz. packets from Jianas Brothers. They are on the web. The instructions on the packet make a concentrated solution designed to be used to treat Colera, dysentery, etc but, when diluted to an ~8% concentration provide sodium, potassium, and glucose. I used it that way successfully for years and only recently switched to a commercial product because it seemed like too much hassle to start adding maltodextrin, glucose, whey protein, etc for more, and more balanced, calories, then trying to get it to dissolve properly. If you're into that route, these packets would provide an excellent base to build on.