Gas gauge not working? I think I fixed it.

thanks Redfish. I almost had it set up to go. I was going to video tape it in case it blew up and killed me, they would know for sure my cause of death was stupidity. I have now set it up so I can add the air from up to 100 feet away. It probably has an ounce or two of gas left in it that I could not get out.
Maybe I should fill it some with water, So if it explodes is will really look nice on video and will mean I need less air volume. I am getting ready to do this in the next 30 minutes, so stop me now if I am playing with death