Graphics settings issue

I have an older computer so I am using reduced graphics settings and dx 9,
and I am trying to find the spectral abyss hellrift which I am told is a pale violet
in color, but I only see red, blue and white hellrifts, no other. (I know that the rift
types appear randomly, but after dozens of tries I assume I would get every type
at least once). I am assuming the reduced graphics settings affect how color
appears. Is there any graphics setting I need to increase to be able to see the
colors I need?
The screenshot shows the only hellrift colors I ever see2

Spectral hellrifts are found in the Westminster Catacombs. Have you looked there?

A few times, but mostly in brompton graveyard