Aquafina vs Dasani
Aquafina is distributed by Pepsi. Dasani is distributed by Coca-Cola.
 Approach to "Purity"
Dasani aims to "enhance" water by adding salts and minerals. Aquafina, on the other hand, aims to remove all salts and minerals from the water to leave pure H20.
Pepsi's Aquafina brand advertises its water as "Pure Water—Perfect Taste". Aquafina strips out all minerals and other substances to create its "pure" water. It’s pure "purified" water and easy on the palate.
Coke's Dasani is "enhanced with mineral for a pure, fresh taste". Note how "pure" appears in both brands taglines—stripped of minerals (Aquafina) and enhanced with minerals (Dasani).
 Purification Technology
Aquafina uses the HydRO-7 purification system, which includes reverse osmosis, charcoal filtration, and ozonation.
Dasani uses the reverse osmosis process for purification.
Some people note that Dasani has a salty taste. This is due to the salts and minerals that are added to enhance Dasani's taste.