I have remedy for the water marble blues - fake it, and stamp it! I have few different stamps I can use, and I'm set for a while. Just imagine - it always comes out perfect, no worries about positioning, and praying that you managed to capture something good on your nails, not on cuticles and surrounding skin. No worries about temperature of the water, or if polish would actually spread...
This pretty grayish-blue is Essence - Blue-jeaned. I was eyeing it in the store for a while, and did not buy it because it is textured! Whatever! Texture is really fine, and I can live with it, and as you can tell, "water marbles" like a dream. I was actually able to stamp with it, as long as your design is not too fine. Thing is, I wanted 2 coats, so I painted another layer with fine brush, and messed it up in the process - my bad. I filled in with two Joe Fresh blues: Wave and Robin's egg. Stamp is Bundle Monster BM-320, and can you believe this is the first time I used it!
I added some stitching using MoYou plate from Fairy tale collection 04 on the other nails to gave it more of blue jeans look.