6BK4, Scary green glow.

[walterbeers]

It's normal I've seen the green glow many times over the years of working on tube type color sets using 6BK4s and similar regulators. The roundie that i'm restoring now the 6BK4 also glows green. As the tube conducts heavier the brighter the glow becomes. Some also glow orange as well. As you lower the brightness or high voltage the glow will get brighter as the tube will conduct heavier.