Strange liquid in glass and thick glass behavior I am doing a chemistry render but I am struggling with my cupric sulfate solution in a flask in Blender : the Volume Absorption node doesn't really works as expected.

I have a too light area and a thin dark zone (instead of the thick one).

I also have a dark area in the thick glass.

Render


Mesh of the thick glass part with sub surface disabled


Node setups
The colors are light shades of blue, darker ones gave a really dark result.


Texture assignment (with normals)


Light Paths


Color Management


I think I gave enough information to solve the problem, but feel free to ask me for more. So what am I doing wrong ?

Thanks for your help in advance.
Finally, I tried several things and I got a better result by reworking lighting and trying a new camera angle. I closed the space where my flask is, added windows, added a ceiling, and added a few area lights at the top. I also tweaked my colors and absorption values. I also separated the interface meshes (now, they aren't connected, but still in the same object).

Here is my result



And here is my CuSO4ToAir material (the only difference with the CuSO4ToGlass is the IOR)



I will mark this answer as solution, but I am still listening to a better solution if you have.