You get a lot more water marks on multi-finish than we used to with the old plasters with the exception of Carlite finish which was a very fine plaster compared with the others available. Multi is also finer than board finish ( if it's still the same) and the other plasters we used to use. I find I don't get water marks if the walls go just right, not needing any water on any of the trowels, so I can only assume that it's the fact that the multi is so fine that causes them.