I am having a problem adjusting the Visible Transmittance of a glass Element (material) below a certain value.

If I set the value to anything below .2, the glass appears to block ALL light. For example, I see a very small step down in light when I use values of .21 and .20, but a value of .19 decreases the light completely.

Is there a limit to Visible Transmittance that I am not aware of either in the software or conceptually?