*Welcome to the forum!* Your nano tanks look nice and stocked! I am a fan of the 40gallon breeder tanks.They have a spacious floor plan and the shorter depth makes access easier for the vertical challenged.
Yes its very stocked I'm thinking of upgrading asap I have a 29g in my room and a media reactor but thinking hard wether to use the 29 as a sump or refugium or DT and get a 20g long for sump space and refugium