Eating 50> carb/day - sodium/potassium ratio 1,5:1 - read Volek And Phinney - 60 year old cyclist - Canada / Mexico at 60' with 50 carb and 1,2:1 up to 2:1 ratio for sodium.
Eating 130-70 carb - sodium/potassium ratio 1:1 - i use it.
More then 150 "normal" ratio - 1500-2300mg of sodium max and 4700mg potassium - ratio sodium/potassium 1:3