Dynamic Y-axis not working on a stacked column chart

Hi all, a newbie here. I have a chemical dataset. Dataset is composed of different experiments (FormID) and monitoring of impurities (ImC, Delta, Total)  accumulation over time (0, 7, 14, etc) on different temperatures (25 and 40).

I have it all working for a separate impurity (see tab "noField" in the shared file). But I want to have a dynamic Y-axis where I will be able to select which impurity I want to look at. For example, in the "noField" tab, on the Y-axis is Average of ImC. I can make another identical plot with Delta or Total on the Y axis, but I wan to have it changed dynamically since in real life there are many impurities that are measured.  In the tab "FieldNotWorking", I created New Field using ImC, Delta and Total (and called it Impurity), then I placed that newly created Field on the Y-axis, but then it is not working. See the attempt that does not work in the tab "FieldNotWorking".

I  am not sure why this is he case and I lost many day and was not sucessful. I do apologize if the answer exist somewhere, I just was not able to locate it and I looked a lot.

Link to pbix file