Snake, you caught me the week after I scraped the sides of it, so its relatively clean, and I have a new camera that I'm still getting used to.
Its actually a hard plastic fish-bagger, like the one the LFS uses to scoop fish out, before bagging them.
The first pair of pictures show it from underwater. You can see the chaeto, the PH, and the 'outlet' holes. I didn't drill enough holes, so some of the water still spills over the top, as well.
Keep in mind, this is on a 30g tank, so it doesn't require massive amounts of chaeto. I think I reduce it by about 1/3 every month or two. The PH is the smallest one Rio makes. Its a POC, but it works in this application.