JD's awesome thread on DIY filter socks inspired me to make a filter for my BioCube 8 setup at work. It's been modded, so the normal filters for it do not work, and I needed something to filter water and a good place for carbon/GFO without adding more equipment to the tank. So, here was my idea:
I made a pattern to fit one of the compartments in the setup, then cut the pattern out of felt. Luckily, JoAnn Fabrics had a remnant that was damaged, so I was able to pick up 1/2 yard of felt for $0.66.
I needed a way to determine which filter pad contained GFO or carbon, so I set the bobbin to either brown or black (for GFO or carbon, respectively) depending on which I was using.
I then sewed mostly around the pad and left an opening to fill it up. Unfortunately, my sewing machine is older than the redwood forest, so it doesn't make the fancy edge stitching like JD was able to do, so I just used the zig-zag switch. Seemed to work fine!
I filled up the pads with GFO or carbon, and sewed the opening closed.
I've made about 4 so far (2 of each) so I can rotate them out on a weekly basis and just throw them away. I'll see how it works on Monday.