This is one of those "well why didn't I think of that?" moments. It seems awesome and I hope it pans out. But really, I came here to comment on the odd phrase

This is one of those "well why didn't I think of that?" moments. It seems awesome and I hope it pans out. But really, I came here to comment on the odd phrase I found in an image caption: "...synthetic freshwater or seawater..." I don't think I've ever heard (seen?) anyone refer to anything water-based as "synthetic" simply because the impurities were added by a human instead of by a riverbed.