Filter socks, and front-end-loader washing machine ??

[Delphinus]

I'm on the fence whether I keep them for my new tank. On my cube it's basically a necessity because the sump length is too short (28" long, fits in the stand, it's a 30" cube) for the amount of flow the sump sees between the skimmer and the sump return itself, so without it, the tank has terrible microbubbles. They do help keep the water polished clean though and also work to prevent a gunk buildup in the sump, so they do have some advantages.