PowerTIG DX200 DC works awesome! A/C mode blew up my Gas-lens!

[spoolxexo]

SO I took a whack at TIG'ing some 1/4" Aluminum plate for the first time.

I have been using the pedal and it's "Your guess is a good as mine" amperage setting.

I had the pedal at about half way and the initial puddle was pretty good, but slow to form.

I turned the pot up to 75% Amps, and struck the arc.

A small poof happened and before I knew it, my Gas lens screens had been melted from a Piece of the tungsten (Red band) that has blown up.

Why did this happen? Too much Argon? 1/16" Tungsten too thin? A/C frequency and balance off?

Thanks for the help guys! Here is a shot of the exhaust I had made on DC mode.