I am ramping up the pressure by putting 2 vaccumes together. it seems to work, so now I will make a supper vacume from say 10 different units. I want to get to the top of Everest! lol :) taking the filter out by its self only added about 500ft. I do more tests than I film and I always make sure the tank can hold before I actually get inside. the barometer is reading inches of mercury. I managed to get about 2 inches in this test almost a full PSI! also I get plenty of ventilat