Excuse my ignorance, but what is the section for that is after the bio balls and the scrubbies? I mean, it looks like you have a bunch of egg crate stacked up there and on the first page it looks like you're saying that's where the mechanical filtration is - but you have the socks for that and (like what was said on an earlier page) wouldn't you want the mechanical filtration before the bio filter?
I'm new to this W/D filter system, so I'm still trying to learn all the ins and outs of it. I'm not second guessing anything you've done, just trying to understand it. Thanks.