How to disable Arena Frames?

[fivesixtysix]

Hello, I'm simply looking for the option to hide the arena frames. I'm currently using Gladius and I can't find a way to disable the default arena frames.

When I toggle the "Enabled" option under /realadv -> HuD -> Unit frames -> Groups -> Arena Frames, it just reverts the arena frames back to the blizzard default ones. And since installing RealUI, I don't have the "Unit Frames" options under "Interface" anymore.