How to Stop Sightglass Boilover?

[RonRock]

Doing a test boil with my Keggle and kept getting boil over out of the sightglass. I am pretty sure it is from bubbles created in the keggle itself from the heated water. Not from burner heat being washed out from under the skirt. Any ideas how to stop this?

 

[Seven]

I'd test it with some sort of heat shielding underneath. My sight glass boiled and became pretty much useless during the wort boil until I added some heat shielding underneath it. Now my sight glass isn't boiling when my wort is boiling and all is right with the world again.