The other cool thing about the Blender solution is that the ratio of diffuse to refraction does not have to be a constant. It can be controlled by more nodes.

Here I used a clouds node to make the ratio variable.

Use gray scale colors to represent the numbers. Black = 0, White = 1. RGB 128 corresponds to (approximately) 1/5 or .5. (It's technically 128/255, which is .502).

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)