I think that you had that backwards, but: For ten years I have used both, depending on which one was on sale. I have 3 tanks (75,90,120), so I have done a lot of water changes. I have never found a difference. I have never examined my water on a microscopic or cellular level, which I'm sure not many have, but I think it depends only on which flavor you prefer. Someone may have some research to back up an opinion (hopefully not by either of the two companies), but I'm giving mine on what I have always had success with, which is both.