This is my first attempt to design a fill & drain with a bell siphon. I have it configured and will test it for another 24 hours. It is late in the growing season and I'm having trouble finding hydroton or pea gravel locally. I will move this indoors and set it up with gravel.
I'll keep the single crayfish and some greens on top. This setup won't be particularly productive, but female rusty crayfish are not nice to tank mates. :)