The bungee cords are really secure. I attach them at the bottom "lip" of the tank, front and back. The tank has to be slightly elevated, but it already is because of the UTH anyway. I used to have ones that went all the way around, but the boyfriend needed some for the car so I adapted for now. The lid is so secure, I need to use a butter knife to get enough leverage to lift the lid a bit so I can slide it open.
They are all in the same room.