I don't water fast so I can't speak about that specifically, but I can give a good answer on oral rehydration mixtures in general. Here's the TLDR I have in a n

I don't water fast so I can't speak about that specifically, but I can give a good answer on oral rehydration mixtures in general. Here's the TLDR I have in a notes file on my phone: A drink made with 6 level teaspoons of sugar and 1/2 level teaspoon of salt dissolved in 1 litre of clean water. Be very careful to mix the correct amounts. Too much sugar can make the diarrhoea worse. Too much salt can be extremely harmful to the child. Making the mixture a little too diluted (with more than 1 litre of clean water) is not harmful. Ideal consumption ~30ml every few mins (or ~90mim for the 1L) I left the child reference in as a copy/paste from... I can't remember which medical source I got it from - although my use has only been for when I or someone else wants to minimise a hangover. I once made this mix for somebody in front of a GP (doctor) who said "wow, that's exactly the 'basic rehydration recipe' we teach when we go to parts of the world where they don't have the education / equipment we have in the UK". But that's the MVP for oral rehydration. A little potassium is good to include, and looking at the commercial tablets I have (that mix with water) they include potassium (193mg / 200ml water) and chloride (350mg / 200ml).