Welcome to the site! I am going to have to look at the instructions but I have not had any problems with compression. I have a hole drilled in the side of the container. It is sealed with duct tape right now but I'm going to re do it with goop. I try not to put too much stuff in there at one time so the ozone can contact more surface area but it has worked when I loaded it up once too. The first few times I used it I ran it longer, especially for my boots until the stink went away. Now I usually just do one or two cycles. I am pretty sure I did breakdown the plastic on one pair of boots, but all of my other boots show no changes. The pair that broke down was a different kind of plastic. I'll post a pic if I can remember I'm away for the weekend now.