Spark is not an electrolyte replacement (although they just announced a stevia sweetened version of spark today! Note: I have not seen other ingredients). Spark is an energy drink with caffeine and vitamins for every (B complex, etc). I would assume bulletproof coffee would be a replacement for that. Although not all ingredients are approved by this group, Spark does not contain maltodextrin. An old formula one did, but they got rid of it a few years ago. Rehydrate is AdvoCare’s electrolyte replacement drink. I just use water and make sure I’m getting enough salt, magnesium, and potassium. I have seen where some use Powerade Zero depending on your tolerance of the sweetener. I have never used it. I just keep a bag of pink Himalayan salt and some magnesium spray in my gym bag.