Now go back to the left column and scroll down until you see "Debuff: Weak Ancient Barrier". Select it.
Click on "Color". (This will bring up a separate window.)
Move the bubble-shaped icon to the red portion of the color circle. Then adjust the brightness using the bar on the right to whatever is comfortable for your eyes. Click "Okay".
Next, go to the tab labeled "Indicators" and select the "Center Icon" on the left column.
Go to the right column and scroll down until you see "Debuff: Weak Ancient Barrier". Click on the checkmark box to enable display.
Healers
If you are using the Grid addon, here's how to display the absorbs for the units: