Just wanted to say great job on the tank setup! I really enjoyed reading about your various DIY workarounds, and your success with the HC carpet is really impressive. Looking forward to seeing where things go next.
Been a little worried about shrimp (8x Amano) escapes on a 20g long myself. There's a lid, but with big gaps. For now it seems they've got too much algae to keep them occupied! But something they also took a real liking to as soon as they were in the tank, and which may have limited escapes for now, was the underside of a piece of driftwood. They basically all congregated there for days on end, just doing there thing. I'm sure there are lots of going theories about shrimp retention, but maybe as your scape starts growing nooks and crannies that twinstar cord won't look so enticing!