Cheers Quiarcus. It's vallejo clear water, so whatever that is!
The really fine cracks under the rocks you can see in the pictures above seem to be getting worse with every layer. I'm not sure what could cause it as I'm putting on really thin layers now.
If I can't get it looking good now, I'm going to hid it with reeds and some of the vallejo sculptable water, like you suggested. Which would involve buying a tub of the stuff, which I'm not thrilled about.