so I don't know that much about this, but as far as I know this is "sweet water". It's a water mix with some sort of sugar in it that makes it work. It's pretty new and people are still finding out what fish they can do it with. From what I know it's more about the fish community than the water itself. I don't know about reefs, but people have been keeping fish just fine in this water, the mane problem is keeping fish that would never see each other in the same tank. From what I have read any salt water fish will push most fresh water fish around for the most part, but there are people that have had some success with this.