I got most of it done. I am surprised how many black worms I have. I gave the 90g several. Many scuds and seed shrimp. The population of seed shrimp is definitely lower than it recently was. The three wild type Neocaridina shrimp are fine. I have removed at least 20 leeches.
Tomorrow I will continue to sift through the substrate. I do not expect to find much. It smells rotten; and has turned black.
Do not put Rooibos tea pieces straight into the tank. It makes it hard to sift through the substrate and to distinguish between black worms and tea.

Crashed tank. This was originally set up as a fish tank with plants and Corydoras to keep the shallow sand substrate healthy. It was then converted to the live food (detritivores). While trying to gently remove the excess mulm with the turkey baster, I discovered that it is mostly devoid of life. The sand is black and the detritus smells bad. In the 2 x 3” section that I worked on last night, I only found 3-5 seed shrimp, about 10 scuds and several black worms. I killed many leeches.
I did not touch the water. I have noticed over the last several weeks that my arm is developing wheals as it leans on the top of the tank when I am harvesting worms. Hopefully, this is just a contact dermatitis to the plastic and not an allergic reaction to the inhabitants of the tank.
I am going to set up a new tank with a handful of crushed coral and maybe small gravel. I will transfer the sponge filter and the extra sponges that are housing worms. I will also try to save the black worms, scuds, shrimp, seed shrimp; sans the snails and leeches.
Live and learn, I guess.

The tank officially has leeches. I counted six young ones today. I am going to take a wait and see approach. There are very few snails on glass. Many have gone to surface. The seed shrimp boom seems to be over. The black worms seem to be doing fine.

Remove two young adult flukes.