My second try at water marble nails

I like this technique so much that even after my first unsuccessful attempt I decided to try it again. This time I've managed to do all my 10 nails and I'm very proud of myself.... but still I need more practice on designs!

I used OPI Ate Berries In The Canaries and Venus di Violet over the white base -Revlon White on White

Water Marble Nail Art

After watching a dozen video tutorials on Youtube (check out Colette, she does some amazing patterns) I have decided that I'll give it a go. I really like this style and it looks so pretty on nails. So I have prepared everything what I needed and started dropping the nail polishes into the water.
Then after about half an hour I managed to do the following pattern. Nothing special, but I was so proud of myself :))
I have used Barry M - Grey and OPI - Grand Canyon Sunset

Then I changed the colours and after another hour of trying....voila...what an amazing pattern! But unfortunately the last one. I'm not sure what I was doing wrong, but the nail polish drops didn't spread out in the water as they should have been. I tried everything - filtered water, bottled water, colder water, warmer water and about 10 different polishes.... So after 2 hours I gave up =(
Nail polishes used: Revlon White on White and Fuchsia Fever

And one picture of my work station. Very messy :-/

Have you ever tried this technique? Any ideas what I was doing wrong? Thanks for your tips in advance :)