I used artifical water produced by Vallejo. You have the gel like one, or still water which is very thin ? I used both, and i must say that i don't recomend any of them.. still water need LOTS of layers, it 'sucks up'.. when you try to apply it you'll see what i mean.. you apply 3mm of it, but when it dry, there is only like 0.2mm of water.. the gel like imitation of water is something similar to white glue. I recomend using real resin, like the one from Andrea, you can get like 5 cm. depth after one pouring and it looks very good. You asked about coloring, Vallejo water doesn't look good colored, you better add color under it. Andrea resin can be colored with normal paint.