Based on the assumption that 220 perfectos are 7X2X2, because i dont know the actual size, then this is true:
The tank typically holds 220 gallons of water, about 1900 lbs over a surface area of 2016 inches on the bottom panel. That is about .94 lbs per in on your bottom piece of glass. Now figure you, say a 150 lb person, standing on two feet, 150 lbs displaced say over 20 inches (while standing) is 7.5lbs per squar inch. That said, I wouldnt stand in my tank... Granted, your surface area would be much more if you were say, sitting on our butt or kneeling down...