I'm trying to make a fluid with something dissolved into it. It's almost opaque but there are some spots of lower density solute. This is why I can't just use nodes on surface alone--I need to be able to have the opacity partly dependent on thickness.
I figured I could use a Principled Volume node and then put a low roughness, max transmission Principled BSDF node on the surface to give it the reflection and physical surface.
It didn't work. I was expecting the cube to look a bit like white watercolor paint or milk mixed with water. Instead, I got a black cube.
What is this and how can I fix it?