Interesting you mention Ultima - I started using it a few weeks ago when Nashbar had a two for one sale of it. It works great for rehydration but I was puzzled that one of the ingredients was iron - 17% of the RDA. Most people don't need extra iron in their diets and I wonder what was the logic in adding it. Does it facilitate the absorbtion of something else? I know it's hard on the stomach for some people and gives the drink a bit of a "vitamin" taste.