Semi-update:
Cherry shrimps alive! Well, at least a couple. Sneaky buggers are only popping out waaay late at night during bathroom visits. They are also dinky--1/2", if that. Hoping they will grow bigger!
Moved ghost shrimpies to time-out bowl as they were being naughty. A squirt of gravel vac from main tank every couple days and fill up when low:
Also, have been trying to set up dirt bowl ~3 gallons. Not working out so well! Plants wilting and covered in whiteish...gunk. Suspect that they might be diseased as the ones from the same bundle I stuck in beta tank also mushed, while moss and riccia seem to be doing ok. IDK.
Pretty gross!